Celso L. Hohmann

Effect of temperature on the development and thermal requirements of Wolbachia-infected and antibiotically cured Trichogramma kaykai Pinto and Stouthamer (Hymenoptera: Trichogrammatidae)

Com o objetivo de entender a influencia da temperatura em alguns parâmetros biologicos de Trichogramma kaykai Pinto e Stouthamer (Hymenoptera: Trichogrammatidae) infectado e nao infectado com Wolbachia (tratado com antibiotico), determinaram-se a duracao do desenvolvimento e as exigencias termicas da progenie dos mesmos sob quatro temperaturas constantes (15, 20, 25 e 30°C), UR 70 ± 5% e fotofase de 14 h, usando como hospedeiro ovos de Trichoplusia ni Hubner (Lepidoptera: Noctuidae). O conhecimento dos efeitos da temperatura e fundamental para ajudar a entender a dinâmica de organismos habitantes do deserto como T. kaykai que estao sujeitos a extremos de temperatura ao longo das estacoes. Parasitoides nao infectados tiveram um desenvolvimento mais rapido a temperaturas mais elevadas (20, 25 e 30°C) do que aqueles infectados. Contudo, parasitoides infectados apresentaram desenvolvimento mais rapido do que parasitoides nao infectados a temperatura mais baixa (15°C). A duracao do desenvolvimento da progenie de parasitoides nao infectados e infectados aumentou de 7,0 e 7,1 dias a 30°C, respectivamente para 37,3 e 36,7 dias a 15°C, respectivamente. Os machos desenvolveram-se mais rapido que as femeas em todas as temperaturas avaliadas. A temperatura base de desenvolvimento da progenie de parasitoides nao infectados e infectados foi 12,0°C e as exigencias termicas 127,71 e 132,10 graus dias, respectivamente.

Host Deprivation Effect on Reproduction and Survival of Wolbachia-Infected and Uninfected Trichogramma kaykai Pinto & Stouthamer (Hymenoptera: Trichogrammatidae)

The effect of temporary host deprivation on the reproduction and survival of Trichogramma kaykai Pinto & Stouthamer was determined by comparing a Wolbachia-infected (thelytokous) and an arrhenotokous line of T. kaykai when reared on Trichoplusia ni Hubner (Lepidoptera: Noctuidae) eggs. The progeny produced by both arrhenotokous and thelytokous females decreased with increasing periods of host deprivation, but arrhenotokous females produced significantly more progeny than thelytokous females regardless of the period of host deprivation (0 to 10 days). They also produced more daughters. Host deprivation did not affect brood size within arrhenotokous or thelytokous lines. However, fewer wasps emerged from hosts parasitized by Wolbachia-infected than by uninfected T. kaykai. A direct relationship existed between longevity and the length of time an arrhenotokous or a thelytokous wasp was deprived of hosts. The longer the deprivation period, the longer they lived. However, arrhenotokous females lived longer than their thelytokous counterparts. These findings showed that temporary host deprivation (up to 10 days) affected both reproductive forms similarly. However, in all conditions studied arrhenotokous wasps produced more progeny and lived longer than their thelytokous counterparts.

Selectivity of neem to Trichogramma pretiosum Riley and Trichogrammatoidea annulata De Santis (Hymenoptera: Trichogrammatidae)

Trichogramma pretiosum Riley and Trichogrammatoidea annulata De Santis are commonly found in avocado and persimmon orchards in northern Parana state. However, their abundance depends on whether insecticides are used or not to control the key lepidopteran pests Stenoma catenifer (Wals.) (Lepidoptera: Elachistidae) and Hypocala andremona (Stoll) (Lepidoptera: Noctuidae), respectively. The aim of this work was to evaluate the effects of an aqueous neem seed extract (ANSE) at 15, 3 and 1.5%, and of an emulsifiable concentrate neem oil (ECNO) at 2.5, 0.5 and 0.25% on lifetime parameters of these trichogrammatids as a way of testing the feasibility of integrating the biological and chemical control methods. Chemicals were applied on Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs before or after parasitization (one, three or five days). ANSE was more deleterious to both parasitoid species than ECNO, regardless of the concentration and the time of application. The chemicals acted on a concentration and time dependent manner. Treating the host with neem before parasitism was less deleterious to wasp emergence, especially for T. annulata. Pre-treatments (24h) of the host eggs with ECNO at concentrations varying from 0.5% to 0.25% did not affect T. pretiosum longevity, but 2.5% reduced T. annulata survival. Feeding wasps with honey mixed with 0.25% ECNO negatively affected T. annulata survival.

Parasitism of Hypocala andremona (Stoll) (Lepidoptera: Noctuidae) eggs on parsimmon trees by Trichogrammatids

The study reports a field survey to determine the presence of parasitism on the leaf defoliator Hypocala andremona (Stoll) (Lepidoptera: Noctuidae) eggs, on parsimmon trees by Trichogrammatids. H. andremona eggs were sampled weekly on two branches/10 trees/orchard during the 2000/01 and 2001/02 crop seasons in Londrina, and during 2000/01crop season in Arapongas, PR, Brazil. In laboratory the eggs were isolated in gelatin capsules and maintained under controlled conditions (26 ± 1oC, 60 ± 10% RH, 14L:10D). Three parasitoid species were identified: Trichogrammatoidea annulata De Santis, Trichogramma pretiosum Riley and Trichogramma bruni Nagaraja. In Arapongas only T. pretiosum was collected. Natural control levels in general were low, but parasitization levels up to 50% were found during the samplings. The potential use of these biological agents to control the lepidopteran pest is discussed.

Argyrotaenia sphaleropa (Meyrick) (Lepidoptera: Tortricidae) in citrus in the State of Paraná, Brazil

Argyrotaenia sphaleropa (Meyrick) is associated with various fruit species in South America. This tortricid was first detected in citrus, Citrus sinensis (L.) Osbeck, in Brazil, in commercial groves in northern Paraná, during the 1994/95-crop season. The aim of this work was to study the biology of this lepidopteran under laboratory conditions (28 +/- 2 degrees C, 70 +/-10% UR, 14h photofase) using the citrus cultivar Pêra. Larvae obtained from egg masses collected in a commercial citrus grove in Rolândia, PR, were individually placed on citrus terminal leaves inside glass shell vials (8.5 x 2.5 cm) until adulthood. A male and a female moth were then transferred to acrylic cages (13 x 10 cm) containing inside a bouquet made with new citrus flush to serve as oviposition substrate. Adults were fed daily with a 10% honey solution. The biological parameters evaluated were duration of development of egg, larval and pupal stages; pupae weight; duration of pre-oviposition and oviposition periods, fecundity and longevity. The length of the egg to adult stage was around 36 days. The pre-oviposition period was almost two days, the oviposition period approximately ten days and the embryonary period around six days. Adult longevity was almost 15 days for females and nine days for males, and the lifetime fecundity was slightly over 180 eggs.