Teresinha Vinha Zanuncio

Hemipterous predators of eucalypt defoliator caterpillars

Abstract In Brazil, plantations of Eucalyptus have increased significantly, mainly as monocultures. As a result of the large planting programmes, damage due to insect attacks and diseases has been registered. Several methods of control have been used, but biological control, by rearing and release of natural enemies, seems to be an efficient method with low cost, and less social and ecological problems than chemical methods. The Forest Entomology Laboratory at the Federal University of Vicosa, in Brazil, has successfully identified the major predators of eucalypt defoliator caterpillars. Studies were concentrated on the description of these insects, their diets, prey, habitat, and also, methods of capture and reproduction in laboratory conditions.

Effect of feeding on three Eucalyptus species on the development of Brontocoris tabidus (Het.: Pentatomidae) fed with Tenebrio molitor (Col.: Tenebrionidae).

Brontocoris tabidus (Heteroptera: Pentatomidae) is an important predator of defoliating Lepidoptera in Brazil, which has been mass produced and released against defoliating caterpillars in Eucalyptus plantations. We aimed to improve the mass production of this predator by providing eucalypt seedlings, in addition to an alternative prey, for its development. The effect of three Eucalyptus species on the development of B. tabidus fed with Tenebrio molitor L. (Coleoptera: Tenebrionidae) pupae, was studied at a temperature of 25.0 - 2.5 o C; a relative humidity of 70.0 - 10.0% and a photophase of 12:12 hours (light:dark). Pupae of T. molitor were provided in each of the following feeding treatments: treatment 1, Eucalyptus urophylla seedlings; treatment 2, Eucalyptus camaldulensis seedlings; treatment 3, Eucalyptus grandis seedlings; and treatment 4, no seedling (only pupae of T. molitor ). Duration of the nymphal phase of the predator was similar in all treatments with plant and prey. It was observed that adults developed from nymphs fed on T. molitor only, had deformed wings and a small abdomen. B. tabidus fed during their nymphal and adult stages with prey together with Eucalyptus seedlings, had improved longevity, higher egg viability and a larger number of eggs and nymphs, than those insects fed only with prey. Therefore, it seems advisable to rear B. tabidus with prey and seedlings of Eucalyptus species, to improve the mass production of this predator for biological control of defoliating caterpillars of eucalypt plantations.

Major lepidopterous defoliators of eucalypt in southeast Brazil

Abstract Lepidopterous defoliators of Eucalyptus have caused great damage to plantations in Brazil, making it necessary to study these important insect pests. This paper presents the results of investigations of major lepidopterous (primary and secondary) pests associated with Eucalyptus plantations in nine regions in southeastern Brazil. Entomological samples were taken from Eucalyptus spp. plantations in the regions of Belo Oriente, Montes Claros, Tres Marias, Alto Sao Francisco and Guanhaes (Minas Gerais State), Cacapava and Sao Jose dos Campos (Sao Paulo State) and Sao Mateus and Aracruz (Espirito Santo State). The insects were collected in light traps and sent to the Forest Entomology Laboratory, Animal Biology Department, Federal University of Vicosa for sorting, counting, cataloguing and identification. Eleven primary and 40 secondary pests of Eucalyptus were identified. The majority of species were in the families Saturniidae, Geometridae, Arctiidae and Notodontidae. The highest populations of insect pests, such as Thyrinteina leucoceraea and Thyrinteina arnobia (Geometridae), Eupseudosoma invluta (Arctiidae) and Glena spp. (Geometridae) were recorded during the cold and dry part of the year, from May to September. Some species, however, were present during the wet part of the year. These included Eacles imperialis magnifica, Psorocampa denticulata and Dirphia rosacordis (Notodontidae).

Immunity of an Alternative Host Can Be Overcome by Higher Densities of Its Parasitoids Palmistichus elaeisis and Trichospilus diatraeae

Interactions of the parasitoids Palmistichus elaeisis Delvare & LaSalle and Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae) with its alternative host Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae) affect the success or failure of the mass production of these parasitoids for use in integrated pest management programs. The aim of this study was to evaluate changes in the cellular defense and encapsulation ability of A. gemmatalis pupae against P. elaeisis or T. diatraeae in adult parasitoid densities of 1, 3, 5, 7, 9, 11 or 13 parasitoids/pupae. We evaluated the total quantity of circulating hemocytes and the encapsulation rate versus density. Increasing parasitoid density reduced the total number of hemocytes in the hemolymph and the encapsulation rate by parasitized pupae. Furthermore, densities of P. elaeisis above 5 parasitoids/pupae caused higher reduction in total hemocyte numbers. The encapsulation rate fell with increasing parasitoid density. However, parasitic invasion by both species induced generally similar responses. The reduction in defensive capacity of A. gemmatalis is related to the adjustment of the density of these parasitoids to their development in this host. Thus, the role of the density of P. elaeisis or T. diatraeae by pupa is induced suppression of cellular defense and encapsulation of the host, even without them possesses a co-evolutionary history. Furthermore, these findings can predict the success of P. elaeisis and T. diatraeae in the control of insect pests through the use of immunology as a tool for evaluation of natural enemies.

Species of Lepidoptera defoliators of Eucalyptus as new host for the parasitoid Palmistichus elaeisis (Hymenoptera: Eulophidae)

Pupae of Thyrinteina arnobia (Stoll) and Thyrinteina leucoceraea Rindge (Lepidoptera: Geometridae) were obtained from Eucalyptus cloeziana F. Muell and Eucalyptus urophylla S.T. Blake plants, respectively. Specimens of a parasitoid emerged from T. arnobia pupae and also found parasitising T. leucoceraea pupae in the field were identified as Palmistichus elaeisis Delvare and LaSalle (Hymenoptera: Eulophidae). This is the first report on P. elaeisis parasitizing T. arnobia and T. leucoceraea pupae in natural conditions in Brazil. P. elaeisis also parasitized these hosts and Bombyx mori Linnaeus (Lepidoptera: Bombycidae), Anticarsia gemmatalis Hubner, Pseudaletia sequax Franclemont, Alabama argillacea Huebner (Lepidoptera: Noctuidae), Dirphia moderata Bouvier (Lepidoptera: Saturniidae) and Halysidota pearsoni Watson (Lepidoptera: Arctiidae) in the laboratory. The production and release of P. elaeisis could be an efficient alternative for controlling Lepidoptera defoliators in eucalyptus plantations.

Effect of plantation age on diversity and population fluctuation of Lepidoptera collected in Eucalyptus plantations in Brazil

A faunistic survey of Lepidoptera associated with eucalyptus was carried out from June 1989 to June 1994 in a plantation at the Vale do Rio Doce Region, State of Minas Gerais, Brazil. Insects were collected every fifteen days with five light traps and divided in primary, secondary and non-pests of eucalyptus as well as a group of nonidentified morphospecies. Twelve primary pests with 5823 individuals; 17 secondary pests with 2757 individuals; 148 non-pests with 8856 individuals and 1179 unidentified morphospecies with 11,834 individuals were collected. The most abundant primary pest species were Stenalcidia grosica and Glena unipennaria (Lepidoptera: Geometridae) while Eacles imperialis magnifica and Automeris illustris (Lepidoptera: Saturniidae) and Idalus admirabilis (Lepidoptera: Arctiidae) were the most abundant secondary species. Differences in numbers of individuals trapped were significantly higher between locations of light traps than between years. There were significantly more species in the last years of this study, but the number of specimens was similar for all years. These results indicate a high environmental stability and suggest that this region is one of the most suitable areas for Eucalyptus plantation in Brazil.

Reproductive strategy of Podisus rostralis (Stal) (Heteroptera: Pentatomidae) females under different feeding intervals

The reproduction and survival of Podisus rostralis was evaluated under different feeding intervals using Tenebrio molitor larvae as food and a continuous supply of bean slices. There was a linear r...

Prey capture ability of Podisus nigrispinus (Dallas) (Het., Pentatomidae) reared for successive generations on a meridic diet

Adults and nymphs of Podisus nigrispinus reared for three and four generations, respectively, on a meat‐based artificial diet were able to find, capture and feed on velvetbean caterpillar (Anticarsia gemmatalis Hüb. (Lep., Noctuidae)) in laboratory and in greenhouse. In laboratory, nymphs reared on artificial diet were more aggressive to their prey than those reared on house fly larvae (Musca domestica L. (Dipt., Muscidae)), an alternative prey currently used for rearing this predatory species. Adults reared on the artificial diet behaved similarly to those reared on house fly larvae. In greenhouse, adults and nymphs of P. nigrispinus previously reared on artificial diet and released on soybean plants (Glycine max (L.) Merr.) exhibited prey capture ability comparable to those reared on house fly larvae. Therefore, predators reared on this meat‐based artificial diet seem to be as suitable for biological control programmes as those reared on house fly larvae.

Fauna de coleoptera coletada com armadilhas luminosas em plantio de Eucalyptus grandis em Santa Bárbara, Minas Gerais

The objective of this research was to study population fluctuation of Coleoptera species in the county of Santa Barbara, Minas Gerais, Brazil in a Eucalyptus grandis plantation. Coleoptera individuals were collected with five light traps during one night every fifteen days from July 1993 to June 1994. A total of 5,641 individuals of this order was collected, being 866 and 4,775 identified at genus and/or species and family levels, respectively. The family with the highest number of individuals was Carabidae with 74.55%, followed by Scarabaeidae and Elateridae with 10.12% and 3.98% of individuals of this group, respectively. Most species collected were Isonychus albicinctus (Scarabaeidae), followed by Colaspis jolivetti (Chrysomelidae) and Cyclocephala laminata(Scarabaeidae) with 412, 317 and 16 individuals which represented 54.50, 36.61 and 1.85% of individuals identified per species, respectively. The region of Santa Barbara presents a diversified fauna of Coleoptera, but with low outbreak possibilities. Population peaks of Coleoptera species ocurred in November and December, when monitoring of these insects is recommended.

Population density of Lepidoptera in a plantation of Eucalyptus urophylla in the state of Minas Gerais, Brazil

A monitoring programme was developed from July 1992 to June 1993 using light traps in a plantation of Eucalyptus urophylla in the municipality of Tres Marias, State of Minas Gerais, Brazil. A total of 437 species of the Lepidoptera order was collected and divided into the following groups: primary pests: 11; secondary pests: 18; species without defined importance to eucalyptus culture: 65; and non-identified species: 343. These four groups had 1295.35, 24.40, 127.20 and 1030.55 individuals per light trap, respectively, with a total of 2477.50 Lepidoptera individuals collected per light trap during this period. Most frequent primary pests were Psorocampa denticulata (Notodontidae), Stenalcidia grosica (Geometridae) and Eupseudosoma aberrans (Arctiidae) which were constant species (present in more than 50% of the collections) with a higher number of individuals during the driest and coldest periods, except P. denticulata , which showed more individuals during the hottest and most humid periods of the year. Faunistic analysis of this area showed a possibility of outbreaks of these primary pests, and mainly of P. denticulata .