Paulo Rebelles Reis

Seletividade de agroquímicos ao ácaro predador Iphiseiodes zuluagai Denmark & Muma (Acari: Phytoseiidae)

The side-effects of agrochemical to Iphiseiodes zuluagai Denmark & Muma (Acari: Phytoseiidae) were studied in laboratory using the residual contact spray method in glass surface. Forty-two plant protection products, used in Brazilian citrus orchards, were tested. Mite mortality and fecundity were evaluated for eight days. Tested products were ranked in toxicity classes, according to IOBC/WPRS system, by the total effect (combination of mortality and reproduction effect). The results showed that ca. 26% of the tested products were harmless (captan, clofentezine, fenbutatin oxide, fosetyl, hexythiazox, copper hydroxide, naled, copper oxychloride, cuprous oxide and tetradifon), 14% slightly harmful (abamectin, chlorothalonil, copper sulphate, thiophanate-methyl (PM) and ziram), 7% moderately harmful (sulfur, parathion-methyl and thiophanate-methyl (SC)) and 52% harmful to the mite (acrinathrin, amitraz, azinphos-ethyl, azocyclotin, benomyl, bifenthrin, bromopropylate, carbaryl, carbosulfan, chlorfenapyr, cyhexatin, dicofol, fenpropathrin, fenpyroximate, mancozeb, mineral and vegetable oils, phosmet, propargite, quinomethionate, triazophos and vamidothion).

Effect of prey density on the functional and numerical responses of two species of predaceous mites (Acari: Phytoseiidae)

Phytoseiidae mites are the most important and studied natural enemies of pest mites. A question frequently raised is whether phytoseiid may reduce high densities of phytophagous mites. Studies of functional and numerical responses may help to answer this question. The aim of this work was to evaluate the potential predation success of Iphiseiodes zuluagai Denmark and Muma and Euseius alatus DeLeon (Acari: Phytoseiidae) on Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae), vector of the citrus leprosis and the coffee ringspot viruses. Bioassays were performed in the laboratory. Adult females of each predator were isolated in arenas made with citrus leaves (3-cm diameter). Immature stages of B. phoenicis were offered as prey, at the following numbers/arena: 1, 2, 5, 10, 20, 30 and 35 (seven replicates), 45 (four replicates), 55 (three replicates) and 70, 100, 125, 200 and 300 (two replicates). The number of killed prey and of eggs laid by the predators was evaluated every 24h, during eight days. Killed prey was replaced daily by new prey. For both predatory mites, a positive and highly significant correlation was found between the numbers of prey offered and killed. The average daily oviposition rate also increased with the number of killed prey. At the lower densities, E. alatus killed and ate more B. phoenicis than I. zuluagai. The opposite was observed at the highest densities. It is possible that E. alatus can reduce B. phoenicis population even at low prey densities, and I. zuluagai can do the same also at high densities. The fact that E. alatus requires less prey than I. zuluagai suggests that its survivorship may be higher than that of I. zuluagai at low prey densities.

Caracterização do ataque da broca dos frutos do pequizeiro

The extractivism of pequi fruits (Caryocar brasiliense Camb.) (Caryocaraceae) is an important option of income, food and employment for the populations living in the savannah regions all over Brazil. However, the natural supply of those fruit is endangered by a great deal of factors, among those stands out a serious pest, Carmenta sp. (Lepidoptera: Sesiidae) making them unsuitable for consumption. The present study aimed to know some characteristics of the responsible insect as well as the way of attacking pequi fruits, damage caused and characteristic symptoms. This work was performed through the analysis of previously collected pequi fruits, both on the plant and soil in the type savannah vegetation in Montes Claros county, Northern Minas and Itumirim, Southern Minas, in Minas Gerais State. In the former county were harvested fruits between 80 - 120 days after anthesis (DAA), while in the last one in two times, 45 and 90 DAA. In each county, collect time and site (plant or soil) were collected 50 fruits for analysis. The evaluated characteristics were: longitudinal and transversal diameter, percentage of damaged fruits, number of worm per fruit and number of chrysalides per fruit. After the analysis of those characteristics, the insects developmental stages were recorded and documented photographycally as to length, coloration and morphology as well as attack symptoms. From this work, we can conclude that the pequi fruit lepidoborer can provoke damage to yield higher than 50 %, destroying all the inside of the fruits. The youngest fruits are the most attacked, being commom to find a single worm in its inside.

Toxicidade de produtos fitossanitários utilizados na cultura do cafeeiro a larvas de Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) e efeitos sobre as fases subseqüentes do desenvolvimento do predador

The objective was to evaluate the selectivity of pesticides used in coffee crops to larvae of Chrysoperla externa (Hagen) and their effects on the subsequent developmental stages of the predator. The treatments in g a.i./L of water were: 1 - endosulfan (Thiodan 350 CE - 1.75), 2 - chlorpyrifos (Lorsban 480 CE - 1.2), 3 - betacyfluthrin (Turbo 50 CE - 0.013), 4 - sulphur (Kumulus 800 PM - 4.0), 5 - azocyclotin (Peropal 250 PM - 0.31), 6 - copper oxichloride (Cuprogarb 500 PM - 5.0) and 7 - control (water). The products were sprayed on first, second and third-instar larvae using a Potters tower. The larvae were individualized in glass tubes and maintained at 25 ± 2oC, RH of 70 ± 10% and 12h photophase. The toxicity of the pesticides was calculated based in their total effect (E) and classified according to recommendations of IOBC. Chlorpyrifos and betacyfluthrin were harmful to first-instar larvae (E > 99%). Endosulfan, sulphur, azocyclotin and copper oxichloride were harmless to first-instar larvae and the others were selective. Chlorpyrifos was also toxic to second and third-instar larvae, and the other compounds were selective (E < 30%). None of the pesticides affected the duration and survival rate of pupae or the sex ratio of the adults originated from treated larvae. Endosulfan, sulphur, azocyclotin and copper oxichloride were harmless to the larval stage of C. externa and did not affect the subsequent stages, so that they can be recommended in IPM programs for the coffee crop.

Sobre a nomenclatura das espécies de cochonilhas-farinhentas do cafeeiro nos Estados de Minas Gerais e Espírito Santo

Root coffee (Coffea arabica L.) mealybugs (Hemiptera: Pseudococcidae) collected in Boa Esperanca, southern Minas Gerais State, were identified as Dysmicoccus texensis (Tinsley) (= bispinosus Beardsley) and these from aerial part collected in Castelo, State of the Espirito Santo, as Planococcus minor (Maskell). However, Brazilian literature mentions other mealybug species of coffee tree as Pseudococcus cryptus Hempel in roots and Planococcus citri (Risso) in the aerial part. Therefore, more than one mealybug species may be occurring in the roots as in aerial part of coffee trees, and the survey and taxonomic studies are necessary before setting a control program, specially biological control.

Biologia de Iphiseiodes zuluagai Denmark & Muma (Acari: Phytoseiidae)

Iphiseiodes zuluagai Denmark & Muma (Acari: Phytoseiidae) is a predaceous mite commonly found on citrus plants (Citrus spp.) in Brazil. With castor bean (Ricinus communis) pollen as food and 25 ± 2 °C, 70 ± 10% RH and 14 hours of photophase, most of the eggs hatched after ca.12 to 24 hours. The larval and protonymph stage duration was ca. 24 hours each, and ca. 48 hours for deutonymph. The life cycle from egg to adult lasted 5-6 days. The intrinsic rate of increase (rm) was 0.122 females/ female/ day, the mean generation time (T) 18.7 days, the net reproductive rate (Ro) 9.82 females/ female and, the finite rate of increase (1) 1.13.

Controle de Brevipalpus phoenicis (Geijskes, 1939) E Oligonychus ilicis (McGregor, 1917) (Acari: Tenuipalpidae, Tetranychidae) em cafeeiro e o impacto sobre ácaros benéficos: I - abamectin e emamectin

O acaro Brevipalpus phoenicis (Geijskes) e importante em cafeeiro (Coffea spp.) por ser o vetor do virus da mancha-anular, doenca responsavel por queda de folhas e ma qualidade da bebida do cafe, e o acaro-vermelho Oligonychus ilicis (McGregor) por reduzir a area foliar de fotossintese. Acaros da familia Phytoseiidae, de varias especies, sao eficientes predadores associados aos acaros-praga. Conduziu-se este trabalho com o objetivo de estudar o controle dos acaros-praga com spirodiclofen e azocyclotin, e o impacto sobre fitoseideos. Em laboratorio foram estudados os efeitos ovicida, topico, residual, topico mais residual e a seletividade fisiologica aos fitoseideos; em casa-de-vegetacao foi avaliada a persistencia no controle as duas especies de acaros-praga; e em campo foi avaliada a eficiencia apenas no controle de B. phoenicis. Os bioensaios foram realizados em arenas de folhas destacadas. O efeito ovicida foi avaliado em ovos no inicio e final de incubacao. Os efeitos residual, topico e topico mais residual foram avaliados pela mortalidade de larvas, ninfas e adultos aos oito dias, e a persistencia ate 30 dias apos a aplicacao. A seletividade aos fitoseideos foi avaliada, pelo efeito na mortalidade e reproducao de femeas adultas, em teste residual em superficie de vidro. Spirodiclofen e azocyclotin (SC) mostraram eficiente acao ovicida, principalmente para ovos de B. phoenicis no inicio de incubacao. Para ovos de O. ilicis, somente o spirodiclofen apresentou efeito ovicida. Em geral, os efeitos topico e residual associados melhoraram a eficiencia dos produtos no controle das fases pos-embrionarias de ambas as especies. O spirodiclofen apresentou seletividade aos acaros predadores, ja o azocyclotin foi nocivo. Em campo, ambos os acaricidas mostram-se altamente eficientes na reducao de todas as fases pos-embrionarias do acaro B. phoenicis, principalmente nas folhas.

Ação de produtos fitossanitários utilizados em cafeeiros sobre pupas e adultos de Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae)

It was evaluated the action of the pesticides endosulfan, chlorpyrifos, betacyfluthrin, sulphur, azocyclotin and copper oxychloride to pupae and adults of Chrysoperla externa (Hagen)(Neuroptera: Chrysopidae). The bioassays were carried out in the Entomology Department of the Universidade Federal de Lavras - UFLA, MG, Brazil. The treatments in g i.a.L-1 of water, were: 1 - endosulfan (Thiodan 350 CE - 1.75), 2 - chlorpyrifos (Lorsban 480 CE - 1.2), 3 - betacyfluthrin (Turbo 50 CE - 0.013), 4 - sulphur (Kumulus 800 PM - 4.0), 5 - azocyclotin (Peropal 250 PM - 0.31), 6 - copper oxychloride (Cuprogarb 500 PM - 5.0) and 7 - control (water). The sprayings were accomplished directly on pupae and adults of green lacewing, using a Potters tower. The pupae were placed in glass tubes and the adults in PVC cages and maintained in climatic chambers at 25 ± 2°C, RH of 70 ± 10% and 12-hour photophase. The experimental design was completely randomized, with seven treatments and ten replicates. Each plot was made up by either four pupae or one couple of C. externa. The pesticides were classified according recommendations of the IOBC. Chlorpyrifos was classified in the class 2 = slightly harmful (30£E£79%) for pupae, and the all the other products were selective and classified in the class 1 = harmless (E 99%) and betacyfluthrin in class 3 = moderately harmful (80£E£99%). Endosulfan, sulphur, azocyclotin and copper oxychloride were harmless to adults, being classified in class 1. The pesticides endosulfan, azocyclotin, sulphur and copper oxychloride can be recommended in coffee pest management programs in association with C. externa, based in the reduced toxicity presented in these products for this predator.

Produtos naturais e sintéticos no controle de Leucoptera coffeella (Guérin-Mèneville & Perrottet, 1842) (Lepdoptera: Lyonetiidae) e seus efeitos sobre a predação por vespas

O controle do bicho-mineiro-do-cafeeiro Leucoptera coffeella (Guerin-Meneville & Perrottet, 1842) e realizado por meio de inseticidas de amplo espectro de acao, capazes de causar desequilibrios biologicos, sendo importante a busca por produtos que apresentem toxicidade a praga e seletividade aos seus inimigos naturais. Objetivou-se, com este trabalho, avaliar a acao dos produtos naturais, extrato pirolenhoso Biopirol® a 2,0; 4,0; 8,0 e 16,0% e azadiractina Nim-I-Go® a 0,25; 0,50; 0,75 e 1,0% em comparacao com os inseticidas sinteticos lambdacialotrina (0,01 mg i.a./mL) e etion (1,5 mg i.a./mL) sobre o bicho-mineiro e seus efeitos sobre vespas predadoras desta praga, em condicoes de campo. Para isto, foi instalado um experimento em uma area de aproximadamente 1,2 ha, em lavoura cafeeira da cultivar Catuai Vermelho, situada em Lavras, MG. As concentracoes do extrato pirolenhoso e de azadiractina avaliadas nao controlaram o bicho-mineiro e nao afetaram negativamente a capacidade predatoria das vespas. Observou-se que etion causou efeito letal as lagartas, logo apos sua aplicacao, decrescendo ao longo do tempo. Lambdacialotrina apresentou menor toxicidade as lagartas logo apos sua aplicacao, seguido por um aumento significativo de controle da praga ao longo do tempo.

Análise temporal e controle da mancha-anular e do ácaro vetor do Coffee ringspot virus

The objective of this work was to evaluate the population fluctuation of the mite Brevipalpus phoenicis, vector of the Coffee ringspot virus (CoRSV) - the causal agent of the coffee ringspot disease -, as well as its distribution in coffee plants, and the effect of acaricides in its control in coffee crops. The experiment was carried out at the municipality of Coromandel, in the region of Alto do Paranaiba, MG, Brazil, during two years. In the second year, the progress of the disease was evaluated, and the relationship between the mite population and disease incidence was determined. Ringspot disease and mites were detected throughout the year, with larger populations and disease incidence in the months with lower rainfall and mild temperatures. Pearson analyses showed negative correlation between the climatic parameters and the mite population. In the analysis of the disease incidence in different periods, a positive correlation was found among the first and subsequent evaluations. Regarding spatial distribution, mite presence was observed in the whole plant; however, leaves are preferred by the adults, whereas the fruit are preferred for oviposition. The acaricides are effective in keeping the mite population at low levels, with consequent reduction of disease incidence.