Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact helpdesk@bioone.org with any questions.
Anastrepha ludens (Loew) (Diptera: Tephritidae) is a major pest of mango and citrus in Mexico. It is usually controlled by applying several strategies in a holistic approach. The entomopathogenic fungus Beauveria bassiana (Bals.-Criv.) Vuill. (Cordycipitaceae) is a biocontrol agent that infects adults of many tephritids pests including A. ludens. In this work, we carried out 4 experiments with the objective of estimating the mortality of A. ludens adults when different conidial concentrations of the fungus B. bassiana were applied to the soil at different humidity, texture, and temperature conditions under controlled laboratory conditions. In a first experiment, mortality ranged from 38.3 to 79.8%, with the highest mortality occurring at a concentration of 800 mg of formulated conidia per kg of soil, while the lowest mortality was recorded at a concentration of 400 mg/kg. In a second experiment, when soils with different texture were investigated at 12% humidity, the pathogenicity of B. bassiana on A. ludens adults was similar in sandy clay soil and sandy loam (64.0% mortality), but was lower in sandy soil with 36.0% mortality. In a third experiment on humidity tests, fly mortality of A. ludens adults ranged from 43.0 to 79.8%, showing the highest mortality at 12% soil humidity and the lowest at 21%. Mortality was similar between 15 to 35 °C (>83%). Emergence of A. ludens adults in the controls ranged between 94.5 and 98.3%. The soil humidity was the major factor that significantly affected fungal efficacy. The study demonstrated the potential of using B. bassiana applied to the soil for management of A. ludens and other tephritids. However, B. bassiana must be evaluated under field conditions before recommendations can be made.
Frequent US port of entry quarantine interceptions of unidentifiable larval Leucothrips (Thysanoptera: Thripidae) species in association with Codiaeum variegatum (L.) Rumph. ex A. Juss. (Euphorbiaceae) ornamental plants from Costa Rica, initiated research to determine if these thrips were an invasive threat to US agriculture. Larval and adult Leucothrips were collected from the new growth leaves of C. variegatum and other plants in Florida and Costa Rica. There were no morphological differences among adult specimens from different hosts in Florida and Costa Rica; all identified as Leucothrips furcatus Hood by comparison with type specimens. However, morphological differences in larvae associated with these adult specimens were evident. DNA sequences of the mitochondrial cytochrome oxidase c subunit 1 gene (COI), and 2 regions of the nuclear ribosomal cistron (rRNA; the complete internal transcribed spacer 2 [ITS2], and a section of the 28S large subunit rRNA) were used to verify that larvae and adults collected at the same site were the same species. Molecular data revealed species level divergence congruent with larval morphological differences.
Although rotenone is widely used as a pesticide, it has a low level of insecticidal activity on Spodoptera litura (F.) (Lepidoptera: Noctuidae). To gain a better understanding of the high tolerance to rotenone, a synergist (cinnamon oil) was added, and the comparative physiological impacts were assessed. After rotenone treatment, a considerable amount of rotenone was discharged in excreta, but extremely low levels were found in the ventral nerve cord and brain. By contrast, the rotenone cinnamon oil treatment group showed an increased amount of rotenone in the ventral nerve cord and brain. The co-toxicity coefficient for rotenone cinnamon was 213, indicating synergism. The midgut cells from insects treated with rotenone alone, and the controls, exhibited no significant differences, whereas those of the rotenone cinnamon oil group had larger intercellular spaces. These findings suggest that rotenone alone could not effectively penetrate the midgut, perhaps accounting for its low toxicity to S. litura. The rotenone cinnamon oil mixture apparently affected midgut cell spacing and membrane permeability, thus effectively increasing rotenone toxicity.
KEYWORDS: red imported fire ant, venom apparatus, piperidine, extraction, GC-MS, hormiga de fuego roja importada, aparato de veneno, piperidina, extracción, CG—SM
The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), produces venom that consists of alkaloids and a small amount of protein. The venom possesses a diversity of bioactivities. Several different techniques have been used for the extraction and analysis of fire ant venom. Here, we tested the quality of venom by comparing alkaloid profiles extracted by different methods such as capillary milking, venom gland dissection, solvent-soaking of ants without venom apparatus, and solvent-soaking of whole ants. The results indicated that whole body solvent-soaking extracts the same alkaloids that are found by dissection of the venom sac or those milked through the sting, suggesting that whole body solvent- soaking adequately extracts venom alkaloids from fire ant workers. Due to its simplicity and efficiency, venom extraction by solvent-soaking followed by conventional silica gel column chromatography can be used for isolating fire ant venom alkaloids for chemical analyses and bioassays.
Orchid bees (Hymenoptera: Apidae: Euglossini) are a diverse and important group of Neotropical pollinators. Numerous chemicals have been used in sampling orchid bees, and species-specific attraction, particularly of males, to these chemicals is well known. However, there have been few studies that have quantified differences in the species composition of orchid bees attracted to particular chemicals. In this study, we compared the abundance and species composition of orchid bees collected with 4 commonly used attractants: benzyl acetate, eucalyptol (or cineole), eugenol, and methyl salicylate. Eucalyptol collected the greatest abundance and species richness of orchid bees. Indicator species analysis revealed that 3 species, Euglossa imperialis Cockerell, Euglossa obtusa Dressler, and Eufriesea mexicana (Mocsáry), were significantly associated with eucalyptol, and 1, Eulaema marcii Nemésio, with benzyl acetate. The multi-response permutation procedure revealed relatively large differences in species composition of orchid bees collected with eucalyptol vs. benzyl acetate and eucalyptol vs. eugenol. Our results showed that eucalyptol and benzyl acetate were the most effective and complimentary attractants, but even less effective attractants such as eugenol may attract novel species.
Termites (Isoptera) are widely believed to be one of the most desiccation-prone insects. They must combat desiccation by locating and efficiently conserving water resources. Termites have evolved morphological, physiological, and behavioral characteristics that aid in the tolerance of desiccation. In 3 studies using 4 termite species, water loss tolerance and relative humidity (RH) preferences of termites exposed to 5 different RH, as well as the use of different water sources, were examined. Our results showed that Coptotermes formosanus Shiraki (Rhinotermitidae) preferred and survived better at high RH and with readily available water sources. Neotermes jouteli (Banks in Banks and Snyder) (Kalotermitidae) also preferred a high RH, but was more capable of tolerating lower RH and a lack of free water than C. formosanus. Cryptotermes brevis Walker (Kalotermitidae) and Cryptotermes cavifrons Banks (Kalotermitidae) did not exhibit greater survival in a certain RH nor when exposed to various sources of water. These two species also did not exhibit a preference for a certain RH.
Extrafloral nectar mediates food-for-protection mutualisms between plants and ants. Ant—plant mutualisms are keystone associations, occurring within a complex web of biotic interactions. As such, these interactions may affect plant fitness in a number of ways, both positive and negative. In Senna mexicana var. chapmanii (Isely) H. S. Irwin & Barneby (Fabaceae), the presence of ants has been shown to reduce herbivory and increase fruit and seed set. These effects, however, are not the result of only one interaction but the balance of many. We conducted a field study to determine the processes by which ants affect reproductive fitness in S. chapmanii. Thirty plants were established in a semi-natural area adjacent to native pine rockland habitat in southern Florida. Ants were excluded from half of the plants by painting a sticky resin (Tanglefoot™) around the base of each stem. Over the course of a single flowering season (Oct–May), we observed the effects of ants on the activity of herbivores, predators, pollinators, and pre-dispersal seed predators. We also observed the overall effects of ants on plant size and reproductive output. Plants with ants were quicker to establish, grew larger, and produced floral displays that attracted more pollinators. Contrary to our expectations, relative pollinator efficiency and rates of pre-dispersal seed predation were unaffected by ants. In S. chapmanii, ants did not appear to affect the outcome of other plant—insect associations, but they affected the scale at which they occurred. Ants facilitated plant growth and establishment in S. chapmanii, with subsequent effects on reproductive investment.
A sexual attractant of some Phyllophaga species (Coleoptera: Scarabaeidae: Melolonthinae), methyl 2-(methylthio)benzoate, was studied alone and in combination with light from a solar-powered light-emitting diode (LED) to determine their comparative attraction potential for Phyllophaga species in a sugarcane crop. Four trap treatments were evaluated: sex attractant, sex attractant plus light, light alone, and a control trap without attractant or light. The number and species of Phyllophaga captured were determined over two 5 mo adult emergence periods from Mar–Jul in 2014 and 2015. Additionally, the cytochrome oxidase I (CO1) gene of the species that responded to the compound was amplified, and a phylogenetic tree was constructed using those sequences and sequences found in GenBank. Two species of Phyllophaga, Phyllophaga brevidens (Bates) (Coleoptera: Scarabaeidae) and Phyllophaga lenis (Horn) (Coleoptera: Scarabaeidae), responded to the compound. The traps with sex attractant plus light treatment captured significantly more beetles than the other treatments. Our results suggest that the combination of methyl 2-(methylthio)benzoate and light can be a relatively selective method for the capture of the males of these species of agricultural importance, and it also attracts some females. Finally, analysis of the sequences of the mitochondrial CO1 gene showed that the Phyllophaga species captured with this compound were phylogenetically related.
Eurhizococcus brasiliensis (Wille) (Hemiptera: Margarodidae) is among the principal pests of Brazilian vineyards. Establishment and spread of this species in vineyards are associated with ants (Hymenoptera: Formicidae). This study determined the diversity of the ant fauna in E. brasiliensis infested vineyards in Rio Grande do Sul and Santa Catarina, the main grape-producing states in Brazil. Underground pitfall traps baited with a honey—water solution and sardines were used to sample ants in the spring—summer and fall—winter periods. Twenty-eight species of ants were identified in Rio Grande do Sul and 15 in Santa Catarina. Linepithema micans (Forel) (Hymenoptera: Formicidae) was the most frequent and abundant species collected in vineyards in both states. Control strategies for ants associated with the spread of E. brasiliensis should focus on L. micans in vineyards.
Joyce Gomes Damascena, Germano Leão Demolin Leite, Farley William Souza Silva, Marcus Alvarenga Soares, Rafael Eugênio Maia Guanabens, Regynaldo Arruda Sampaio, José Cola Zanuncio
Leucaena leucocephala (Lam.) de Wit (Fabaceae) is widely used to regenerate degraded landscapes in tropical and subtropical regions and serves as a protein source for animals in agrosilvopastoral systems. Thus, our objective was to assess the spatial distribution of insects on the tree crown (vertical: upper, middle, and basal canopy; horizontal: north, south, east, and west) and leaf surfaces (adaxial and abaxial) of L. leucocephala. Phytophagous insects, natural enemies, and pollinators were quantified fortnightly in 20 trees for 2 yr. North-facing tree branches had the greatest numbers of phytophagous insects, natural enemies, and pollinators. Branches facing west had the most species-rich and biodiverse phytophagous and pollinator assemblages, whereas for natural enemies, species richness and biodiversity were greatest on branches facing north or south. The greatest numbers of individuals and highest levels of species richness of phytophagous insects, natural enemies, and pollinators were observed in the upper and middle parts of the L. leucocephala canopy. The most individuals and highest levels of species richness and biodiversity for phytophagous insects, natural enemies, and pollinators were observed on the abaxial face of L. leucocephala leaves. The species with the highest abundance and k-dominance (common or constant species) on L. leucocephala trees were the phytophagous insects Trigona spinipes F. (Hymenoptera: Apidae: Meliponinae) and Tropidacris collaris Stoll (Orthoptera: Romaleidae) and the natural enemies Camponotus sp.2 (Hymenoptera: Formicidae) and Brachymyrmex sp. (Hymenoptera: Formicidae). These results can inform strategies related to pest control and maintenance of natural enemies and pollinators in L. leucocephala plantations. Biopesticide application, for example, may be more effective at eliminating target organisms if directly applied on their preferred sites, and a targeted application can minimize negative effects for non-target organisms.
For the sterile insect technique to be successful, sterile males need to mate with wild females, transfer an ejaculate and inhibit females from remating. This study evaluated the capacity of irradiated Anastrepha ludens (Loew) (Diptera: Tephritidae) males of the genetic sexing strain Tapachula 7 (Tap-7) for inducing the sexual refractory period (time between the first and second mating) of wild females. The following factors were evaluated: 1) irradiation versus no irradiation of male pupae, 2) the age at which male pupae were irradiated (72, 48, and 24 h before adult emergence), and 3) male sexual experience (virgin, once mated, and twice mated). There was no effect of irradiation or age at irradiation on male ability to inhibit female remating or on sexual refractory period. However, wild females had shorter refractory periods when mated with virgin Tap-7 males, compared with males that previously had mated once or twice. We suggest that because inhibition of remating in A. ludens is determined by the full male ejaculate, virgin Tap-7 males are probably delivering smaller ejaculates compared with sexually experienced males. This study increases our knowledge of the reproductive biology of the genetic sexing strain of A. ludens.
Aedes albopictus Skuse (Diptera: Culicidae) was tested for resistance to permethrin, bifenthrin, and malathion using Centers for Disease Control and Prevention (CDC) bottle bioassays and topical toxicology assays on adults and larval bioassays. Eggs were collected from 3 locations across St. Johns County, Florida, raised to the F3 generation and compared with an insecticide susceptible laboratory strain. Results from CDC bottle bioassays with permethrin indicate no significant differences between the 3 wild-type strains and the laboratory strain but suggest the possibility of resistance in 1 strain. Bottle bioassay results for malathion were inconclusive. Topical toxicological results for adults and bioassays for larvae showed a significant difference in permethrin resistance between the control strain and 1 of the wild-type strains. Results from this project indicate that insecticide susceptibility testing should be a regular part of mosquito surveillance programs. Upon detection of resistance, detailed dose response bioassays should be performed to quantify the resistance and mechanisms in local vector populations.
KEYWORDS: insect pest, development time, reproduction, survival, life table, insectos plagas, tiempo de desarrollo, reproducción, sobrevivencia, tabla de vida
Tirathaba rufivena Walker (Lepidoptera: Pyralidae) is a major insect pest of Arecaceae such as Areca catechu L. (areca), Cocos nucifera L. (coconut), and Elaeis guineensis Jacq. (African oil palm). The larvae feed mainly on the palm flowers, fruits, and leaves, leading to the dropping of flowers and fruits, and they have caused economic damage and crop losses. In order to provide a foundation for the forecasting and scientific management of this pest, the effect of temperature on the development time, survival, and reproduction of T. rufivena reared on A. catechu was studied at 7 constant temperatures (16, 20, 24, 28, 32, 36, and 40 °C). The lower development threshold temperature and the effective accumulated temperature for the completion of the life cycle were 13.4 °C and 1,428.6 degree-days, respectively. The highest survival rate (30.0%) occurred at 28 °C. Eggs failed to survive at 16 and 40 °C. The population trend index (I = 19.04) and net reproductive rate (R0 = 10.40) were highest at 28 °C. The net reproductive rate (R0 = 4.13), intrinsic rate of increase (rm = 0.0334), and finite capacity of increase (λ = 1.0340) were lowest at 20 °C. The mean generation time (T0 = 18.70) was shortest at 36 °C. The population doubling time (PDT = 7.77) was shortest at 28 °C. Based on these results, we concluded that temperatures from 28 to 32 °C were most suitable for the development of T. rufivena reared on A. catechu.
Light trapping is a common method for monitoring and capturing insects such as the invasive agricultural pest, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae). Efforts to develop more effective trapping methods for H. halys have led to research investigating the response of this insect to potentially exploitable stimuli. A behavioral study was conducted to examine the response of H. halys to various light stimuli. Seven intensities (0 [control: dark], 0.1, 10, 50, 75, 100, and 155 lx) of white light were tested. The most attractive intensity for H. halys was 75 lx for adult males and females. Nymphal instars 2 to 5, adult males, and adult females were also exposed to 75 lx white light. Adult males were significantly more attracted to the light than any other life stage. Adults were also exposed to green, orange, red, white, and yellow light. All colors tested were attractive to H. halys. White light was significantly more attractive than the other tested colors. The findings of this study suggest that the incorporation of a white light into H. halys traps may increase the number captured.
Marcus V. Masson, Wagner de S. Tavares, Fabricio de A. Lopes, Amanda R. de Souza, Pedro J. Ferreira-Filho, Leonardo R. Barbosa, Carlos F. Wilcken, José C. Zanuncio
Blue gum chalcid, Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae), causes galling damage to Eucalyptus species (Myrtaceae) in various regions of the world, but has been controlled effectively by its primary parasitoid, Selitrichodes neseri Kelly & La Salle (Hymenoptera: Eulophidae). The objectives of this study were to evaluate the recovery of S. neseri after its initial release on Eucalyptus plants in Brazil and to provide data on its biology. Selitrichodes neseri was imported from South Africa to Brazil for the biological control of L. invasa, in Mar 2015, and recovered from Aug 2015 to Dec 2016. Successful recovery of this parasitoid shows its potential to become established in the field. Seedlings of 2 hybrids obtained from crosses between rose gum Eucalyptus grandis W. Hill. ex Maiden and flooded gum Eucalyptus urophylla S. T. Blake and between Eucalyptus sp. and (river red gum Eucalyptus camaldulensis Dehnh. × E. grandis) showed potential as hosts for culture of S. neseri on L. invasa in the laboratory because up until the adult parasitoid emergence these seedlings did not wilt. When reared at 25.1 to 26.0 °C, the total number of parasitoids and the proportion of male parasitoids were highest, relative to hosts reared at 26.1 to 27.0 °C. Peak emergence of S. neseri occurred 28 d after parasitism.
Most studies on the essential oil of nutmeg (Myristica fragrans Houtt,; Myristicaceae) have been laboratory based. To our knowledge, this is the first study describing the practical application of the essential oil of this species in the greenhouse for controlling the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Three concentrations (10, 5, and 2.5 mg/mL) of the ethanol-extracted essential oil of M. fragrans were prepared. In laboratory experiments, fumigation toxicity was evaluated by applying 0.1 mL of extracted oil onto a filter paper (6 cm diameter) that was attached to the inside of the cap of a 100 mL glass jar containing 20 whiteflies; mortality was recorded 1, 2, 4, and 8 h after application. For assessment of contact toxicity, a tomato leaf was treated with 0.1 mL of the essential oil extract solutions and placed in cages containing 20 whiteflies each; the mortality was recorded at 3, 6, 12, and 24 h of the bioassay. For determination of the repellency effect, 2 leaves, 1 treated with extracted oil and another with the control solution, were placed in cages, and 20 insects were released into each cage; repellency was observed after 24, 48, and 72 h. In the greenhouse, 2 potted plants were placed in a cage; 1 was treated with extracted oil and the other was treated with a control solution; 100 whiteflies were released into the cage, and repellency and anti-oviposition effects were observed at 24 and 48 h of the bioassay. Maximum fumigation toxicity (79.17 ± 3.00%), contact toxicity (72.50 ± 4.23%), and repellency (76.67 ± 7.15%) were observed at 10 mg/mL in the laboratory experiments. The maximum repellency (58.33 ± 3.50%) and anti-oviposition (46.11 ± 5.38%) effects were observed at 24 h of exposure in greenhouse tests. These results suggest that the essential oil of M. fragrans was toxic, repellent, and prevented whitefly oviposition in laboratory and greenhouse tests. Further studies are recommended to assess the bioactivity of the chemical components of the essential oil on other insect species.
The oxhorn bucida tree, Bucida buceras L. (Combretaceae), occurs widely in the southern Florida urban forest. It is commonly attacked by 2 arthropod species, an eriophyid mite, Eriophyes buceras Cromroy (Acari: Eriophyidae), and a caterpillar, Garella (Characoma) nilotica (Rogenhofer) (Lepidoptera: Nolidae). Caterpillar frass and mite-induced galls cause severe staining of sidewalks, streets, and vehicles underneath the tree canopy. The staining is so aesthetically annoying that dissatisfied homeowners remove the trees. Studies were conducted over a 4 yr period at 2 locations to evaluate systemic insecticide treatments against these pests. In Naples, during both 2013 and 2014, trees receiving dinotefuran soil—root drench or acephate trunk injections showed slightly reduced staining possibly due to caterpillar suppression. During 2015 and 2016 in Coral Gables, abamectin trunk injections resulted in excellent reduction in gall formation and staining. Abamectin trunk injections were most reliable in reducing property owner complaints and preserving the benefits of mature oxhorn bucida trees in the urban forest. This treatment represents an environmentally rational approach with none of the drawbacks associated with foliar applications or soil drenching.
The soybean pod borer, Leguminivora glycinivorella Matsumura (Lepidoptera: Tortricidae), is an economically significant soybean pest in northeastern Asia. Serine proteases are crucial enzymes responsible for protein digestion in herbivorous lepidopterans. In this study, a gene (Spbtry1) encoding a soybean pod borer serine protease was cloned from the organism's midgut. The Spbtry1 open reading frame encoded a 269 amino acid protein with a predicted molecular mass of approximately 29 kDa. Alignment of Spbtry1 with trypsins and chymotrypsins from other insects revealed a high degree of conservation in the putative catalytic domain region. Analysis by reverse transcriptase polymerase chain reaction indicated that Spbtry1 was specifically expressed in the midgut, its transcript existed constitutively in the larval stage, and its expression was highest in the 3rd instar larval stage. RNA interference indicated that Spbtry1 expression levels decreased on diets containing Spbtry1 double-stranded RNA (dsRNA). Larvae had significantly lower body weight (18.7 ± 0.25 mg in the Spbtry1 dsRNA-fed group versus 30.1 ± 0.78 mg and 29.9 ± 0.88 mg in the phosphate buffered saline (PBS) and green fluorescent protein (GFP) dsRNA-fed groups, respectively (Student's t-test, P < 0.01) and higher mortality (43.8%) than the control groups (20.8% in PBS-treated and 19.5% in GFP dsRNA-treated) after 15 d, suggesting that Spbtry1 is important for soybean pod borer larval growth and development.
KEYWORDS: persea mite, invasive species, native origin, cryptic species, ácaro cristalino del aguacate, especie invasora, origen nativo, especie críptica
Oligonychus perseae Tuttle, Baker & Abbatiello (Acari: Tetranychidae) is an economically important foliar pest of avocados from Mexico. Invasive O. perseae populations became established throughout the commercial avocado system in California (USA) during the early 1990s, but the putative geographic origin(s) of the California O. perseae populations has not been investigated. To address this shortcoming, a series of population genetic analyses for O. perseae populations representative of a broad geographic sample range was conducted. This study identified a single mitochondrial cytochrome c oxidase subunit I (COI) haplotype match between O. perseae populations collected in California with those from 4 municipalities in Michoacán, Mexico, part of the presumptive native range of this pest. Interestingly, this haplotype also was collected from avocados at 2 locations in Baja California, Mexico, and it was identified from a representative sample from Israel where O. perseae is an invasive avocado pest. Molecular data confirm the likely Mexican origin of invasive O. perseae populations in California, and may help delimit the geographic area to be searched for coevolved natural enemies of O. perseae that could be introduced into California as part of a future classical biological control program targeting this pest. Moreover, molecular results uncovered significant and concordant genetic divergence in both mitochondrial (COI) and ribosomal DNA markers, i.e.,internal transcribed spacer 2 (ITS2) and a section of the 28S gene region, pointing to the potential occurrence of a cryptic species complex within O. perseae. The implications of these findings on future taxonomic and molecular work for O. perseae are discussed.
A Mississippi Delta native strain (NI8 ARSEF8889) of Beauveria bassiana (Bals.-Criv.) Vuill. (Cordycipitaceae), isolated from Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), was tested on green lacewings, Chrysoperla rufilabris (Burmeister) (Neuroptera: Chrysopidae) at 4 spray concentrations (7.02 × 104, 105, 106, and 107 spores per mL) to evaluate effects on reproductive rates and adult life expectancy of this insect predator. The application method simulated atomized spray, and concentrations tested were similar to those used to measure impacts of the fungus on L. lineolaris. Significant effects of B. bassiana on C. rufilabris adults were found, and the severity of impact depended on the concentrations tested. Beauveria bassiana impacted all demographic measurements of C. rufilabris reproduction and survival. Intrinsic and finite rates of increase and gross and net reproductive rates of adults treated with the highest concentrations tested were significantly decreased, whereas doubling time increased for adults treated with the lowest test concentrations. Based on these observations, C. rufilabris will be affected by sprays of B. bassiana targeted at L. lineolaris if adults are present at the time and location of treatment. The measured lethal concentration, LC50, of 2.11 viable spores per mm2 compares to an LC50 of 2.75 spores per mm2 determined previously for L. lineolaris. Higher concentrations of spores per mm2 were required for sporulation (SR50) of the entomopathogenic fungus on C. rufilabris (13.60 viable spores per mm2) than concentrations required for mortality (LC50).
KEYWORDS: thrips, mycoinsecticide, biopesticide, chemical control, cryptic species, chilli thrips, micoinsecticida, biopesticida, control químico, especies crípticas, thrips de chili
The chilli thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae), is a cryptic species complex of at least 9 distinct species, 2 (South Asia 1 and East Asia 1) of which exist in the USA. To integrate chemical insecticides and mycoinsecticides into the preventive and curative tactics used for S. dorsalis, we evaluated 10 older and newer chemical insecticides and 3 mycoinsecticides against S. dorsalis South Asia 1, a dominant member of the species complex in the USA. An insecticide was considered effective when it induced greater than 70% mortality of larvae or adults. The older insecticides (acetamiprid, clothianidin, thiamethoxam [foliar application], and imidacloprid [drench application]) were found to be efficacious in reducing S. dorsalis populations in both curative and preventive situations (≥7 d after treatment). Among insecticides with newer chemistries, foliar application of spinetoram, cyantraniliprole, tolfenpyrad, and formulations of chlorantraniliprole thiamethoxam were effective for both preventive and curative control (≥10 d after treatment). Among mycoinsecticides, Isaria fumosorosea Wize (Cordycipitaceae) was effective in suppressing thrips curatively (≥10 d after treatment). In the insecticide rotation field trial, effectiveness of a Chenopodium (Amaranthaceae) extract and 3 mycoinsecticides alternated with spinetoram was comparable to spinetoram treatment alone. Because S. dorsalis South Asia 1 is a serious pest of several economically important crops in many counties of Florida and Texas, and an emerging pest in California, this study is important in providing information to vegetable and ornamental plant growers regarding effective insecticides with different modes of action that can be rotated to suppress S. dorsalis, and delay the evolution of insecticide resistance. The results also suggest retention of effective products for an extended period in the marketplace.
Seasonal abundance and spatial distribution of melonworm, Diaphania hyalinata L. (Lepidoptera: Crambidae), on yellow squash were studied during 4 crop-growing periods in 2014 in Homestead, Florida. The abundance of D. hyalinata larvae ranged from a minimum during Dec 2014 (1.3 ± 0.0 larvae per 2 leaves) when temperatures were relatively low (15–20 °C), to a maximum in Sep 2014 (6.6 ± 0.1 larvae per 2 leaves) when temperatures were relatively high (24–26 °C). The abundance of small larvae (L1 L2) was relatively greater, with a maximum of 7.1 ± 0.3 larvae per 2 leaves, as compared with medium-sized larvae (L3 L4) (2.4 ± 0.1 per 2 leaves) and large larvae (L5) (2.4 ± 0.1 larvae per 2 leaves) throughout the year. The abundance of large larvae was consistently low over the entire year. Diaphania hyalinata distributions tended to be aggregated (b > 1) during the crop-growing periods during May, Jun–Jul, and Sep 2014, when the population densities were relatively high, but were uniform (b < 1) during Dec 2014, when the population densities were low. A weak but statistically significant positive linear relationship existed between temperature and larval abundance. The results from this study will help squash and cucurbit growers of south Florida in monitoring melonworm infestations in the field and in developing a knowledge-based management program.
Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) is an important natural egg parasitoids of pest insects in the agricultural environment, being used as a form of biological control, and it may be affected by the Bacillus thuringiensis (Bt) toxin present in transgenic plants widely used in Brazil. The aim of this study was to evaluate the effect of Bt maize pollen fed to adults of the parasitoid T. pretiosum Riley (Hymenoptera: Trichogrammatidae) reared in the eggs of the alternate host Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). Three treatments (diets) were compared: pollen from Bt maize, pollen from non-Bt maize, and 10% honey solution (control). Each treatment consisted of 50 T. pretiosum females that were freshly emerged and mated (between 24 and 36 h old). Biological characteristics indicative of the efficiency of T. pretiosum as a biological control agent were evaluated for 4 generations. The results suggest that the consumption of pollen did not affect the evaluated biological characteristics, such as percentage of parasitism, sex ratio, and number of individuals reared per host egg, in any of 4 generations. Thus, we showed that Bt maize is compatible with the use of T. pretiosum for biological control.
This study investigated nuclear markers in Coptotermes formosanus Shiraki and Coptotermes gestroi (Wasmann) (Isoptera: Rhinotermitidae) that can be used as a diagnostic tool to detect F1 hybrids from field samples. Six microsatellite markers were compatible for both parental species and hybrid termites and were optimized so that a standard gene library can be built for the south Florida Coptotermes populations.
Stegasta bosqueella Chambers (Lepidoptera: Gelechiidae) is one of the principal pests of Brazilian peanut crops. Traps made from plastic bottles and baited with molasses sugar can be used to attract S. bosqueella. Molasses-baited traps are a promising tool for the monitoring and control of this insect.
In Chile, the invasive and noxious pest Vespula vulgaris (L.) (Hymenoptera: Vespidae) was first reported in 2011 in the Araucanía region and is currently distributed between Araucanía and Magallanes regions. In Mar 2015 (autumn), during an ongoing monitoring of funnel traps by the Servicio Agrícola y Ganadero, a fungus-infected individual was collected. The fungus was identified morphologically as a species of Hirsutella (Hypocreales: Ophiocordycipitaceae). This is the first report of any Hirsutella species on V. vulgaris in Chile. No in vitro cultures were successfully established from the infected insect.
The Asian citrus psyllid (Hemiptera: Liviidae) transmits a bacterium responsible for huanglongbing, a serious citrus disease. Insecticidal control of the psyllid is a key tactic used to manage the disease, but host plant resistance may hold some promise and clues in the search for alternative tactics. Results of a field survey revealed that relatively large infestation densities of the psyllid developed on conventional Citrus (Rutaceae) and citrange (Rutaceae) cultivars but not on any of 6 Poncirus trifoliata (L.) Raf. (Rutaceae) cultivars. Poncirus trifoliata is a species closely related to Citrus, and citranges are hybrids of sweet orange and P. trifoliata. Reduced colonization by the psyllid on P. trifoliata was largely a result of reduced rates of oviposition. Poncirus trifoliata resistance to oviposition was not observed in 4 citrange cultivars.
José Salazar Zanuncio-Junior, Maurício José Fornazier, David dos Santos Martins, Juliana Chamorro-Rengifo, Renan Batista Queiróz, Alciro Lamão Lazzarini, Paulo Sérgio Fiuza Ferreira
The family Tettigoniidae is associated with grassland damage in several countries, but there are few reports of tettigoniids causing damage to other crops. Specimens of katydids were found damaging banana fruits in Brazil. A survey of their occurrence was conducted, and the damage to banana fruits was quantified. Specimens were identified as Meroncidius intermedius Brunner Von Wattenwyl (Orthoptera: Tettigoniidae). This is the first report of damage caused by this species to an economic crop, and to banana. Symptoms and frequency of damage to banana crops, and behavior of M. intermedius, are discussed.
In Tucumán (northwestern Argentina) during 2013 and 2014, Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) and Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) were found infesting organically grown blackberries in the humid piedmont region (Monte Grande, Famaillá). In 2016, only A. fraterculus was found infesting organically grown blackberries and raspberries in the temperate semiarid region (Tafí del Valle), where studies conducted in prior years showed coexistence of both fruit fly species with prevalence of C. capitata over A. fraterculus, but in other fruit species. In this study, we found that A. fraterculus had a remarkable preference for raspberries over blackberries. These are the first records of fruit fly occurrence in Rubus (Rosales: Rosaceae) in northwestern Argentina and expand the range of host species for fruit flies in the region. Fruit fly infestation levels in blackberries in the humid region were very low, whereas fruit fly infestation in the semiarid region was relatively high. Based on our observations, we hypothesize that spring rains, soil moisture, and relative humidity determine the time of appearance of fruit flies in blackberries in the humid region. Fruit fly abundance should be tracked for several more years to test this hypothesis. In addition, fruit flies were not recovered from fruit samples of the blackberry cultivar Navaho, which is interesting from both an agronomic and scientific perspective.
Native to Australia Gonipterus platensis Marelli (Coleoptera: Curculionidae) is the main beetle defoliator of eucalyptus worldwide, causing damage in various regions in which it was introduced, where its management relies mostly on biological control with the parasitoid Anaphes nitens (Girault) (Hymenoptera: Mymaridae). In this report, we present the first laboratory evidence of efficient predation by Podisus nigrispinus Dallas (Hemiptera: Pentatomidae) on G. platensis larvae. This predatory species is native to Brazil and a promising biological control agent for use in the integrated pest management of G. platensis.
The sugarcane weevil, Acrotomopus atropunctellus (Boheman) (Coleoptera: Curculionidae) is an increasingly important sugarcane pest in Argentina. Its emergence period overlaps with early stages of sugarcane phenology. This research assessed the preference of A. atropunctellus for shoot size and the effect of damage on shoot survival. Acrotomopus atropunctellus preferred to feed on large- and mediumsized shoots, regardless of sex. However, older plants were resistant to injury. Also, the number of punctures produced by females was 1.6 times greater than that produced by males. Avoiding late planting or harvest dates could be a useful tactic for mitigating A. atropunctellus incidence in sugarcane crops.
Pest and beneficial arthropods were collected in a ‘Tifton 85’ bermudagrass pasture in north central Florida to assess their impact on forage production. The primary pests were Auchenorrhyncha (leafhoppers and spittlebugs), grasshoppers, grass loopers, plant bugs, fall armyworms, and stinkbugs. Major beneficial arthropods included spiders, damsel bugs, big-eyed bugs, and small possibly parasitoid wasps. The pest populations did not increase to obvious damaging levels during 35 d growing periods after the grass had been mowed to heights of 8 or 15 cm. Thus, pest arthropods probably can be managed by grazing or periodically mowing ‘Tifton 85’ bermudagrass.
This article is only available to subscribers. It is not available for individual sale.
Access to the requested content is limited to institutions that have
purchased or subscribe to this BioOne eBook Collection. You are receiving
this notice because your organization may not have this eBook access.*
*Shibboleth/Open Athens users-please
sign in
to access your institution's subscriptions.
Additional information about institution subscriptions can be foundhere