Marcelo Fialho de Moura

Seletividade fisiológica de inseticidas a vespidae predadores do bicho-mineiro-do-cafeeiro

The selectivity of the insecticides chlorpyrifos, deltamethrin, dimethoate, ethion, monocrothophos and permethrin to the predatory wasps Apoica pallens Fab., Brachygastra lecheguana Latreille and Polistes versicolor versicolor Olivier (Hymenoptera: Vespidae) was studied, in laboratory, using 50% and 100% of the dosages used for controlling the coffee leafminer, Perileucoptera coffeella Guerin-Meneville (Lepidoptera: Lyonetiidae). Deltamethrin was selective in favour of P. versicolor versicolor and A. pallens. Ethion showed median selectivity in favour of P. versicolor versicolor and A. pallens and good selectivity to B. lecheguana. The other insecticides were not selective in favour of the predatory wasps. The order of tolerance to deltamethrin was: P. versicolor versicolor > A. pallens > B. lecheguana. To ethion, the order was: B. lecheguana > P. versicolor versicolor > A. pallens. Chlorpyrifos, deltamethrin, dimethoate, monocrothophos and permethrin presented similar toxicity to the wasps in both dosages used. On the other hand ethion reduced its impact on A. pallens and P. versicolor versicolor when applied in subdosages.

Selectivity of insecticides to predators of aphids

Estudou-se a seletividade dos inseticidas cipermetrina, diclorvos, diazinon, etion, fenitrotion, malation, metamidofos, paration metilico, permetrina, pirimicarbe e vamidation para adultos dos predadores Cycloneda sanguinea (L.) e Eriopis connexa (Germ.)(Coleoptera: Coccinellidae). Folhas de tomateiro foram imersas em caldas inseticidas nas doses utilizadas para o controle dos pulgoes Myzus persicae (Sulzer) e Macrosiphum euphorbiae (Thomas) em tomateiro e tambem na metade das doses recomendadas. Os fatores em estudo foram os inseticidas, as doses, as especies de predadores e o sexo para C. sanguinea. Vamidation e o pirimicarbe foram os inseticidas mais seletivos a C. sanguinea seguidos do etion e diclorvos (3,2; 6,7; 49,7 e 52,5% de mortalidade, respectivamente). Para E. connexa o pirimicarbe foi o mais seletivo seguido pelo etion e cipermetrina (1,96; 71,28 e 81,92% de mortalidade, respectivamente). Os machos de C. sanguinea foram mais tolerantes que as femeas ao etion (33 e 66,5% de mortalidade) e permetrina (61 e 100% de mortalidade, respectivamente). A toxicidade da permetrina a E. connexa e do etion as femeas de C. sanguinea foi menor quando estes inseticidas foram aplicados em subdose (74,4 e 25% de mortalidade, respectivamente) do que quando estes foram aplicados na dose recomendada (100 e 66,5% de mortalidade, respectivamente) para o controle de pulgoes no tomateiro.

Conventional sampling plan for the green leafhopper Empoasca kraemeri in common beans

Abstract:  A conventional sampling plan for the leafhopper Empoasca kraemeri Ross & Moore (Auchenorrhyncha: Cicadellidae) in common beans (Phaseolus vulgaris L.) is presented based on samples from 51 commercial fields. The research encompassed three phases. The first phase had the objective of determining the most suitable leaf to be used as a precise and representative sampling unit. In the second phase of the project, the available sampling methods for E. kraemeri were compared, including the approach identified in the first phase. In the third phase, the theoretical frequency distribution of the sampling data was assessed and the number of samples necessary for the sampling plan was established. The best leaves to sample adult leafhoppers were the fourth and the fifth from the apex, while the best leaf for sampling nymphs was the fifth from the apex. The best sampling technique for nymphs and adults was the beating of the apical leaves against a plastic tray. The sampling data obtained with this technique were fit to a negative binomial distribution with common aggregation parameter for adults (Kcommon = 1.04) and nymphs (Kcommon = 0.47). This sampling plan required 16.8 and 31.2 min to be carried out at an expense of US

Seletividade de inseticidas a três Vespidae predadores de Dione juno juno (Lepidoptera: Heliconidae)

0.31 and US

Sampling plan for Thrips (Thysanoptera: Thripidae) on cucumber

0.54 for sampling adults and nymphs in a field, respectively.

Seletividade de inseticidas, utilizados no controle de Grapholita molesta (Busch) (Lepidoptera: Olethreutidae) em pêssego, a Vespidae predadores

Among insects that attack passion fruit, Dione juno juno (Lepidoptera: Heliconidae) is considered the most dangerous plague. The selectivity of the insecticides fenthion, cartap, malathion and deltamethrin to the predatory wasps Polybia fastidiosuscula, Polybia scutellaris and Protonectarina sylveirae (Hymenoptera: Vespidae) was studied based on these insecticide toxicities to their prey Dione juno juno. Concentration-mortality regression lines were obtained and the estimated lethal concentration of insecticide to 90% (LC90) of the individuals were used for the calculation of the differential selectivity index and tolerance index. Deltamethrin was selective in favor of P. scutellaris and P. fastidiosuscula and showed intermediate selectivity to P. sylveirae, while cartap showed intermediate selectivity to all three species of predatory wasps. Malathion was selectivite to P. sylveirae and showed intermediate selectivity to P. fastidiosuscula. The predatory wasps P. sylveirae and P. fastidiosuscula were more tolerant to cartap than P. scutellaris and P. sylveirae was more tolerant to malathion than P. fastidiosuscula and P. scutellaris.

Seletividade de inseticidas a Doru luteipes (Scudder, 1876) (Dermaptera: Forficulidae) e Cotesia sp. (Hymenoptera: Braconidae) inimigos naturais de Ascia monuste orseis (Godart, 1818) (Lepdoptera: Pieridae)

This work determines the best technique, sampling unit and the number of samples to compose a sampling plan for Frankliniella schultzei (Trybom) and Thrips palmi (Karny) (Thysanoptera: Thripidae) on cucumber. The efficacy of three sampling techniques: leaf beating on a plastic tray, direct counting of insects on the lower leaf surface, and whole leaf collection in bags were compared in nine commercial cucumber crops using three sampling units (a leaf from a branch located in the apical, median or basal third of the canopy). The number of samples was determined based on the relative variance and the economic precision for the best technique and sampling unit. The direct counting of insects on the apical third of the plant canopy was the best sampling technique for F. schultzei based on one leaf surveyed per plant using 38 plants per field. The best sampling technique for T. palmi was the leaf beating on a tray using one leaf of the apical third per plant and 35 plants per field. When joining both species, the best sampling system was the direct counting on the apical third, and it requires sampling one leaf per plant using at least 35 plants per field. These results facilitate the decision-making for the management of thrips on cucumber and aggregate the benefits of the correct decision for the adoption of strategies for population reduction.

Sequential sampling plans and economic injury levels for Empoasca kraemeri on common bean crops at different technological levels

The selectivity of the insecticides carbaryl, deltamethrin, fenitrothion, fenthion, malathion, naled, methyl parathion and trichlorfon to the predators Protonectarina sylveirae (Saussure), Polistes versicolor versicolor (Olivier) and Protopolybia exigua (Saussure) was studied in laboratory using 50 and 100% of the recommended dose for the control of Grapholita molesta (Busch) (Lepidoptera: Olethreutidae) in peach orchards. The insecticides fenitrothion, fenthion, methyl parathion, naled, and trichlorfon showed no selectivity in favour of the wasps at the full recommended dose, all of them causing 100% mortality among the predators except for trichlorfon which caused 96.9% mortality to P. sylveirae. Carbaryl and malathion were selective in favour of P. versicolor versicolor (18.6 and 6.7% mortality, respectively), and deltamethrin was selective in favour of P. versicolor versicolor (3.6% mortality) and P. exigua (11.8% mortality). P. sylveirae was more susceptible to deltamethrin than P. exigua and P. versicolor versicolor. P. versicolor versicolor was more tolerant to malathion and carbaryl than P. sylveirae and P. exigua. Deltamethrin, malathion and naled were less lethal to P. sylveirae when applied at the lower dose; while the same happened to carbaryl and malathion for P. exigua.

Sequential sampling plans and economic injury level for Empoasca kraemeri on different technological levels of common bean crops

This work aimed to study the selectivity of the insecticides carbaryl, deltamethrin, methyl parathion, permethrin and trichlorfon in favor of the predator Doru luteipes (Scudder) (Dermaptera: Forficulidae) and of the parasitoid Cotesia sp. (Hymenoptera; Braconidae) in relation to the control of the kale leafworm Ascia monuste orseis (Godart) (Lepidoptera: Pieridae). LC90 were determined for A. monuste orseis, and these were used as discriminatory doses to evaluate the degree of selectivity of the insecticides. Deltamethrin and permethrin were highly selective in favor of D. luteipes. Deltamethrin was intermediate selectivity in favor of Cotesia sp., while permethrin was not selective in favor of this parasitoid. Trichlorfon was highly selective in favor of fourth instar nymphs and adults of D. luteipes, and it was intermediate selectivity in favor of Cotesia sp. and first instar nymphs of the predator. Carbaryl was intermediate selectivity in favor of Cotesia sp., but it did not show selectivity in favor of D. luteipes. Methyl parathion did not show selectivity in favor of D. luteipes and Cotesia sp. Adults of D. luteipes were less sensitive to deltamethrin, permethrin and trichlorfon than adults of Cotesia sp. and the inverse happened with carbaryl. Both natural enemies presented high sensibility to methyl parathion. Fourth instar nymphs of and adults of D. luteipes were more sensitive to methyl parathion and trichlorfon than first instar nymphs. Both nymphs and adults of D. luteipes presented similar sensibility to the carbaryl, deltamethrin and permethrin.

Plano de amostragem do biótipo B de Bemisia tabaci na cultura do pepino (1)

BACKGROUND Empoasca kraemeri is an important pest on common bean crops at different technological levels. However, for this pest on this crop, economic injury levels have not yet been determined and plan for sequential sampling plans has not yet been developed. Thus, the objectives of this research were to develop E. kraemeri sequential sampling plans and to determine economic injury levels in the common bean at different crop technological levels. RESULTS Common bean plants tolerate low attack intensities of this pest (up to 1 adult plant-1 ). However, with an increase in attacks, there is a reduction in grain production by the plants. The economic injury levels were 0.48, 0.39 and 0.35 adults sample-1 (leaf beating on a tray) for crops with low (1200 kg ha-1 ), medium (1800 kg ha-1 ) and high (2400 kg ha-1 ) technological levels, respectively. Sequential sampling plans and the standardized plan produced similar decisions. However, in these decisions there was a time saving of more than 60% compared with the standardized plan. CONCLUSION All three economic injury levels determined and the sequential sampling plans developed in this study are suitable for incorporation into integrated management programs for common bean pests because they can be used by farmers operating at various technological levels to make adequate and rapid decisions.