Melon genotypes with resistance to Liriomyza sativae Blanchard (Diptera: Agromyzidae).

The vegetable leaf miner (Liriomyza sativae) is considered one of the main melon pests, causing serious problems for producers in all growing regions. A promising type of pest control has been use of resistant cultivars, in isolation or associated with other types of control. This study aimed to evaluate the resistance of melon genotypes to L. sativae. Twenty-one melon genotypes and one commercial "Goldex" hybrid (susceptibility pattern) were evaluated in two experiments. In the first experiment, we observed the non-preference of L. sativae for oviposition and feeding by quantifying the number of eggs and feeding punctures, both on the adaxial side and on the abaxial face of the leaves. In the second experiment, we observed the antibiosis effect through L. sativae larval and pupal viability. Genotype CNPH 06-1047-341 showed the lowest preference for oviposition (high resistance), with low egg values on both leaf sides (0.3 eggs/plant). In genotypes CNPH 06-1047-313, CNPH 06-1047-346, CNPH 11-1071-27, CNPH 11-1071-39, CNPH 11-1071-43, and CNPH 11-1071-53, we observed a higher preference for the adaxial side, whereas for the other genotypes and the commercial hybrid there was no discrimination between leaf sides. In relation to antibiosis, genotypes CNPH 06-1047-339, CNPH 06-1047-333, CNPH 06-1047-330, CNPH 06-1047-334, CNPH 06-1047-331, CNPH 06-1047-343, CNPH 10-1056-313, CNPH 06-1047-346, and CNPH 06-1047-341 presented lower larval and pupal viability. Genotype CNPH 06-1047-341 was the least preferred for oviposition and feeding and the most promising as a source of resistance to L. sativae.

Dwarf cashew antibiotic and antixenotic resistance to the whitefly Aleurodicus cocois.

The aim of the present study was to identify Aleurodicus cocois resistant genotypes among five dwarf cashew clones available in the germplasm bank of Embrapa/Centro Nacional de Pesquisa Agroindústria Tropical. Free-choice and no-choice tests were applied in order to evaluate the relative attractiveness of the clones and the oviposition preferences, egg-to-adult development times and adult emergence rates of the pest. In comparison with other clones, PRO143/7 exhibited the lowest attraction to the whitefly and was least preferred for oviposition in the free-choice test. Conversely, CCP76 attracted the highest number of A. cocois and was preferred for oviposition. In the no-choice test, the rates of emergence of adults from clones BRS274, CCP76 and PRO143/7 varied between 53.0 and 56.8%, values that were significantly lower (p < 0.05) than those of clones BRS226 and EMBRAPA51, which were 72.34 and 75.16%, respectively. Some of the cashew clones tested showed antibiotic (CCP76, PRO143/7 and BRS274) and antixenotic (PRO143/7 and BRS226) resistance to A. cocois. These clones are good candidates for use in breeding programs of cashew.

Population dynamics and infestation of Holopothrips fulvus Morgan (Thysanoptera: Phlaeothripidae) in dwarf cashew genotypes.

The objective of this study was to evaluate the Holopothrips fulvus Morgan (Thysanoptera: Phlaeothripidae) population dynamics and to identify dwarf cashew genotypes less infested by the pest in 2015 and 2016, under field conditions. H. fulvus population evaluations were carried out by monthly observations in the plants and using a score scale varying from 0 to 4. H. fulvus infestation occurred from October to December, and in the cashew genotypes CAP 112/8, CAP 121/1, CAP 131/2, CAP 145/2, CAP 145/7, CAP 128/2, CAP 120/4, CAP 123/6, CAP 130/1, and CAP 157/2 was dependent on the flowering period of the crop in 2015. In 2016, there was dependence in all evaluated genotypes between H. fulvus infestation and the cashew flowering period. In 2015, no significant differences were observed between the evaluated genotypes regarding H. fulvus infestation. In 2016, genotypes CAP 105/5, CAP 143/7, CAP 150/3, CAP 155/2, CAP 158/8, CAP 161/7, CAP 163/8, CAP 31, CAP 71, CAP 92, CAP 113, CAP 120, CAP 155, CAP 165, CAP 106/1, CAP 111/2, CAP 127/3, CAP 157/2, and BRS 226 were less infested. H. fulvus occurs from October to December and we could identify the dwarf cashew genotypes less infested by the pest.

Dwarf-cashew resistance to whitefly (Aleurodicus cocois) linked to morphological and histochemical characteristics of leaves.

BACKGROUND: The cashew whitefly (CW), Aleurodicus cocois, is an important pest of cashew in Brazil. The use of resistant plants may be an effective strategy for the control of this pest. In a preliminary assay, we found that dwarf-cashew clones show different levels of resistance to CW. Here, we hypothesized that such resistance is associated with morphological characteristics of cashew leaves and their content of phenolic compounds. RESULTS: We determined (i) the attractiveness and suitability for oviposition of five dwarf-cashew clones towards CW, (ii) the leaf morphology and chemistry of those clones, and (iii) the relationship between leaf characteristics and resistance to CW. In greenhouse multiple-choice assays, PRO143/7 and CCP76 showed, respectively, the lowest and highest counts of both CW adults and eggs. Scanning electron microscopy (SEM) analysis revealed that PRO143/7 and EMBRAPA51 have, respectively, the highest and lowest numbers of leaf glandular trichomes. We found a negative correlation between number of trichomes in the abaxial surface of cashew leaves and CW oviposition. In addition, confocal microscopy analysis and histochemical tests with ferrous sulfate indicated a higher accumulation of phenolic compounds in the resistant clone PRO143/7 relative to the other clones. Dwarf-cashew clones did not significantly differ based on the number of leaf epicuticular striations, and the thickness of both leaf lamina and the epidermal layer. CONCLUSION: The resistance of dwarf-cashew plants to CW is associated with an elevated number of trichomes and accumulation of high levels of phenolics in leaves. Additionally, the contribution of epicuticular striation density and thickness of leaf lamina/epidermal layer are insignificant. © 2019 Society of Chemical Industry.

The predator Coenosia Attenuata Stein (Diptera, Muscidae) on cultivated plants from Brazil

ABSTRACT Coenosia attenuata Stein (1903) is a predatory fly that is commonly found in greenhouses and open fields preying on whiteflies, leafminers, psocopterans and other insects. The species is widespread in the Old World and its distribution has expanded in recent times to Neotropical countries including Chile, Colombia, Costa Rica, Ecuador and Peru. We report here for the first time the presence of C. attenuata in Brazil, occurring in different sites in the State of Ceará (Northeastern Brazil). Expansion of the distribution range of this muscid to the eastern parts of South America opens up the possibility of applying the beneficial predator as a biological control agent for protected crops of the region.

The predator Coenosia Attenuata Stein (Diptera, Muscidae) on cultivated plants from Brazil.

Coenosia attenuata Stein (1903) is a predatory fly that is commonly found in greenhouses and open fields preying on whiteflies, leafminers, psocopterans and other insects. The species is widespread in the Old World and its distribution has expanded in recent times to Neotropical countries including Chile, Colombia, Costa Rica, Ecuador and Peru. We report here for the first time the presence of C. attenuata in Brazil, occurring in different sites in the State of Ceará (Northeastern Brazil). Expansion of the distribution range of this muscid to the eastern parts of South America opens up the possibility of applying the beneficial predator as a biological control agent for protected crops of the region.

Identification and pest status of Holopothrips fulvus (Thysanoptera: Phlaeothripidae) on dwarf-cashew crops in northeastern Brazil

Abstract Cashew, Anacardium occidentale L. (Anacardiaceae), is one of the most important sources of agricultural income in northeastern Brazil, but many of the arthropods associated with the crop have yet to be identified. We describe here for the first time the damage caused by Holopothrips fulvus (Morgan) (Thysanoptera: Phlaeothripidae) to dwarf-cashew trees cultivated in the municipality of Pacajús, Ceará, Brazil. Leaf tissue injuries were caused by the sucking mouthparts of the insect and were characterized by dark necrotic spots on the epidermis that resulted in yellowing, wilting and, ultimately, abscission of the leaves. H. fulvus also fed on developing kernels and pseudofruits producing injuries that manifested in the form of chlorotic specks. Additional information is given on the pest status and important aspects of the morphology of the insect, including sexual dimorphism, redescription of the adults and description of the second instar larvae.