Reproduction of Trichospilus diatraeae ( Hymenoptera : Eulophidae ) parasitizing pupae of Eupseudosoma involuta ( Lepidoptera : Arctiidae ) a lepidopteran defoliator in Brazil

Sao Paulo State University (UNESP) Faculty of Agronomic Sciences Department of Plant Protection, PO Box 237, Zip code 18603-970, Botucatu, SP

Defoliating caterpillars are the second most impor tant group of pests in eucalyptus plantations in Brazil, only behind leaf-cutting ants.In the past decade new species of eucalyptus defoliating lepidopterans have appeared in the countr y.Eupseudosoma involuta (Seep 1852) (Lepidoptera: Arctiidae) is considered a primar y pest of eucalyptus in several regions of Brazil.Balut & Amante (1971) reported its occurrence in Eucalyptus saligna, E. alba, E. grandis, and is considered one of the main pests of eucalyptus in São Paulo state, normally associated with outbreaks in E. aberrans (Pereira 1992).It is known that this pest causes damage to the lar val stage (caterpillar defoliating), and presents the risk to human health, because it is a stinging caterpillar.
The attacks of defoliating caterpillars cause partial or total defoliation in plants.In the case of eucalyptus, inter feres with the rate and balance of internal physiological processes of plants, affecting growth and formation of the biomass of the trunk (Espindola & Gonçalves 2000).
Natural enemies are known to have great impacts on the population dynamics of forest Lepidoptera in various ecosystems (Dwyer et al. 2004).Nevertheless, the relative infl uence of natural enemies on populations of forest Lepidoptera is highly depending on the species considered (Paritsis et al. 2012).
Thereafter, the females were removed, and containers with E. involuta pupae were maintained in a climatic chamber at 26 ± 2 ºC, 70 ± 10 % relative humidity and a 14 h photophase, as described by Paron (1999), since the best rearing conditions provide higher progeny and shorter egg-adult duration.The following parameters were determined: level of parasitism, number of emerged and not emerged parasitoids and duration of the egg-adult cycle.The pupae of E. involuta were dissected to evaluate the non-emerged parasitoids.
The experimental level of parasitism reached 80 %, with an emergence rate of 80 %.A mean of 89.4 ± 0.9 (SE) parasitoids per pupa emerged in laboratory conditions, while only 1.3 ± 0.4 (SE) parasitoids per pupa did not emerge.Under these conditions the T. diatraeae egg-adult cycle was 19.4 ± 0.8 (SE) days in E. involuta pupae.These results demonstrate for the fi rst time, under controlled conditions, the ability of T. diatraeae to parasitize the pupae of E. involuta, a species of the Arctiidae family (Fig. 1).
W ith regard to biological control of lepidopteran forest pests in Brazil, T. diatraeae has found a favorable environment since abiotic factors that af fect the per formance of this  field are shown in parasitoids advantageous in forest environment of the agricultural environment, since the microclimate forestr y, characterized mainly by a reduction of the light that penetrates through the cover of trees, thereby decreasing the temperature inside the culture, increasing moisture, and decreasing the strength of the winds allowing the parasitoid has been established in fi eld.In a forest setting, pupae of T. arnobia have been collected on eucalyptus in Minas Gerais state (Pereira et al. 2008).
More studies are needed to determine the potential of T. diatraeae for the biological control of lepidopteran pests in Brazilian eucalyptus plantations, as this biocontrol agent could possibly reduce the use of chemical and biological insecticides for pest control in eucalyptus.
e Lymantriidae(Zaché et  al. 2011b).Parasitoids used in this test were collected on pupae of Iridopsis sp.(Lepidoptera: Geometridae) in Curvelo, Minas Gerais state, Brazil.E. involuta pupae had been reared under room conditions on E. urophylla plants in the experiment area of the Forest Pest Biological Control Laboratory, São Paulo State University (Unesp) in Botucatu, São Paulo state, Brazil.