Flávio Neves Celestino

Side Effects of Fungicides Used in Cucurbitaceous Crop on Trichogrammaatopovirilia Oatman & Platner (Hymenoptera: Trichogramatidae)

Trichogramma spp. (Hymenoptera: Trichogrammatidae) can control Diaphania hyalinata Linnaeus (Lepidoptera: Pyralidae). On the other hand, pesticides may reduce the efficiency of natural enemies. The objective was to evaluate the side-effects of fungicides used in the production of cucurbitaceous crops on Trichogramma atopovirilia Oatman & Platner parasitizing D. hyalinata eggs. The fungicides used in bioassays were: azoxystrobin (0.08 g active ingredient [ai] L -1 ), chlorothalonil (2.00 g ai L -1 ), mancozeb (1.60 g ai L -1 ), tebuconazole (0.25 g ai L -1 ) and thiophanate-methyl (0.49 g ai L -1 ). Cardboards with 30 D. hyalinata eggs previously immersed in fungicide solutions and distilled water (control) were offered separately to 20 newly emerged T. atopovirilia females in glass tubes. Parasitism, parasitism reduction, emergence, sex ratio, and number of individuals per egg were evaluated. The fungicides chlorothalonil, thiophanate-methyl and tebuconazole reduced parasitism of T. atopovirilia by 43.37, 27.64 and 18.51%, respectively. However, parasitism with azoxystrobin (79.21%) was higher than the control (67.37%) (P ≤ 0.05). Chlorothalonil, thiophanate-methyl and tebuconazole reduced emergence by 73.77, 75.62 and 79.35% (P ≤ 0.05), respectively. Azoxystrobin and thiophanate-methyl reduced the sex ratio by 0.77 and 0.76 (P ≤ 0.05), respectively. Fungicides did not reduce the number of individuals per egg. The fungicides azoxystrobin and mancozeb were selective for T. atopovirilia for most studied parameters suggesting that these products must have the priority in crop disease management to allow efficient biological control of T. atopovirilia against D. hyalinata.

Influência do substrato alimentar sobre o desenvolvimento de Diaphania hyalinata L. (Lepidoptera: Crambidae)

The aim of this research was to evaluate the biological behaviour of melonworm at different natural and artificial diets. Squash cultivar jacare, cucumber, summer squash and an artificial diets developed by Hensley & Hammond for the sugarcane borer were tried. The research was carried out in the Laboratorio de Entomologia do Centro de Ciencias Agrarias of the Universidade Federal do Espirito Santo, in climatized room at 25 ± 1oC, relative humidity of 70 ± 10% and 14h photofase. The caterpillars fed on each substrate during the whole life cycle. Differences in duration of the larval period, larvae and pupae survival, adult longevity and number of eggs were registered between the substrates. The results show that the best diet for rearing is the artificial one. Between the natural diets the cucumber showed the best results.

Toxicidade de óleo de mamona a Helicoverpa zea e a Trichogramma pretiosum

e 3,0% (v v -1 ). A acao do oleo de mamona sobre T. pretiosum foi determinada mediante testes de seletividade e suscetibilidade. As maiores mortalidades de larvas foram observadas no tratamento por contato com as menores concentracoes (0,5 e 1,0%), enquanto com as concentracoes intermediarias (1,5; 2,0 e 2,5%), nao houve diferenca entre as vias de aplicacao. A maior concentracao testada (3,0%), o tratamento por ingestao proporcionou mortalidade superior aquela obtida por contato. O numero de ovos parasitados por T. pretiosum, no teste de seletividade, foi afetado negativamente pelo oleo de mamona, contudo, os demais parâmetros avaliados quanto a seletividade e a suscetibilidade nao foram afetados. O oleo de mamona reduz a sobrevivencia de larvas de H. zea tanto por ingestao quanto por contato. Alem disso, nao prejudica o desenvolvimento de T. pretiosum, desde que as pulverizacoes sejam realizadas apos as liberacoes do parasitoide. Termos para indexacao: Ricinus communis, broca-grande, parasitoide de ovos. Toxicity of Castor bean oil on Helicoverpa zea and Trichogramma pretiosum

First report of parasitism of the Trichogramma bruni Nagaraja (Hymenoptera: Trichogrammatidae) in eggs of urbanus proteus (L.) (Lepidoptera: Hesperiidae) in snap beans (Phaseolus vulgaris) ( L.)

Aiming to verify the presence of eggs parasitoids of the genus Trichogramma, for using in the biological control of insects pests, were collected eggs from long tailed skipper butterfly, a lepidopteran defoliator of snap beans, which presented eggs with parasitism characteristics (dark eggs). The eggs were taken to the laboratory were 44.9% of parasitism was verified. Viability was 96.3%, with an average of 6.6 individuals per egg and a sexual ratio of 0.93. Male specimens were identified as Trichogramma bruni Nagaraja. It is the first report of parasitism in this host and culture.

Seletividade de inseticidas, recomendados para cucurbitáceas para Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae) em condições de laboratório

Selectivity of pesticides used in cucurbits to Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae) The cucurbit borers Diaphania spp. are major cucurbit pests, causing losses of up to 100% in production. Biological control with the parasitoid Trichogramma is an alternative for reducing the use of insecticides. The objective of this study was to evaluate the selectivity of the active ingredients abamectin, chlorfenapyr and thiacloprid to Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae). For this purpose, 20 newly emerged females of T. atopovirilla were confined individually in glass tubes (2.5 cm diameter x 8.5 cm in length), with 30 eggs of Diaphania hyalinata (Linnaeus) (Lepidoptera: Pyralidae) glued on a small cardboard strip that was previously immersed for five seconds in chemical solution. The active ingredients abamectin, chlorfenapyr and thiacloprid did not af fect the T. atopovirilia parasitism. However, chlorfenapyr reduced larval emergence. Abamectin and thiacloprid can be therefore recommended for the Integrated Pest Management, as they proved to be the most selective to T. atopovirilia in D. hyalinata eggs.

Influência da densidade de ovos de Diaphania hyalinata (L.) (Lepidoptera: Crambidae) na capacidade de parasitismo de Trichogramma exiguum Pinto & Platner e Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae)

The effects of the egg density of Diaphania hyalinata (L.) on several biological parameters of Trichogramma exiguum Pinto & Platner and T. pretiosum Riley were investigated. For that, 24h-old egg masses were isolated in glass tubes (15 replicates; 1 egg mass = 1 replicate), and offered to parasitization by a newly-emerged female of T. pretiosum or T. exiguum 24h at the proportion of one female to 5, 10, 15, 20, 25, 30, 35 and 40 eggs of D. hyalinata. The following parameters were evaluated: number of parasitized eggs, number of individuals per egg, viability and sex ratio. Trichogramma exiguum parasitized more eggs than T. pretiosum when more than 25 eggs were available per female. The percentage of emergence was satisfactory to T. pretiosum in densities up to 15 eggs/female and up to 20 eggs/female for T. exiguum. The number of individuals per egg was not statistically different in both species except in the density of 25 eggs/female. It can be concluded that T. exiguum performed better than T. pretiosum at larger clutch sizes, as T. exiguum parasitization capacity increased as a result of the size of the host clutch size.

Desenvolvimento de Oligonychus ilicis em Coffea canephora sob diferentes temperaturas

Oligonychus ilicis (McGregor) (Acari) (Tetranychidae) is one of the most important pests of Coffea canephora Pierre & Froehner. In this study, the effect of different temperatures in the development of red mite in C. canephora leaves was evaluated. Eighty adult females were placed in 40 cages to oviposition containing 4 cm leaf discs at 21, 24, 27, 30 and 33 oC. To evaluated embrionary development two randomly selected eggs were allowed to complete development. After larvae hatch, evaluations were performed each 12 hours to determine the survival and larval period. To evaluate longevity one male was transferred to a cage with one female to mate. The thermal threshold of development and thermic constant were determined to egg adult period of development. The development period of immature stages of O. ilicis decreased as soon as the temperature increased. The stages of egg, larvae, protochrysalidae, protonymph, deutochrysalidae, deutonymph and teleiochrysalidae ranged from 10.4 to 4.3, 2.4 to 1.2, 2.0 to 1.0, 2.3 to 1.2, 1.9 to 1.0, 3.0 to 1.5 and 2.3 to 1.0 days, respectivelly. The tempera- ture increase affected the period of egg adult development and adult longevity The thermal threshold of development was 9.0 oC to egg-adult period and thermal constant was 256.4 GD. At laboratory conditions, temperatures between 24 and 30 oC favours the mite development in C. canephora. The thermal threshold of development does not constrain the O. ilicis occur- rence with C. canephora under field conditions in the State of Espirito Santo, Brazil.