Vanda Pietrowski

Selectivity of Beauveria bassiana and Metarhizium anisopliae to Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae)

Trichogramma pretiosum Riley and the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae are efficient biological control agents and are thought to be used jointly. In here, we investigated if these entomopathogens could have any side-effects on T. pretiosum. Therefore, 1 x 8 cards containing sterilized eggs of Anagasta kuehniella (Zeller) that were sprayed with 0.2 ml of B. bassiana or M. anisopliae (1.0 x 10(9) conidia/ml) were offered to a T. pretiosum female for 24h (30 cards/fungus = 30 replicates). Afterwards, females were isolated in glass tubes. The control group was sprayed with sterile distillated water + Tween 80 (0.01%). In addition, 60 cards with sterilized eggs of A. kuehniella were submitted to parasitism by females of T. pretiosum for 24h. Of these cards, 30 were sprayed with B. bassiana or M. anisopliae and 30 with distillated water + Tween 80 (0.01%), and observed daily until parasitoid emergence. Metarhizium anisopliae decreased parasitoid emergence and caused confirmed mortality. Therefore, field and semi-field experiments should be conducted for a final assessment of the side-effects of these entomopathogens on Trichogramma as a ways to develop a control strategy in which both can be used.

First record of Beauveria bassiana (Hyphomycetes: Moniliales) on adults of cassava lace bug Vatiga manihotae (Drake) (Hemiptera: Tingidae) in Brazil

Adults of Vatiga manihotae (Drake) were collected on cassava plantation (Manihotae esculenta Crantz), fecula branca variety, in Marechal Cândido Rondon, West region of Parana state, Brazil, showing symptoms of fungi infection. Isolation and fungi identification procedures were performed. After that, Kochs postulates were used to prove the link between the fungus and insect and i noculated insects showed symptoms similar to the previously observed. Fungus was identified as Beauveria bassiana and caused the death of 14% of the insects 10 days after inoculation. This is the first record of natural occurrence of this species of fungus infecting V. manihote and further studies should be conducted to evaluated new isolates to control of this species.

Occurrence of lace bug Vatiga illudens and Vatiga manihotae (Hemiptera: Tingidae) in Mato Grosso do Sul, midwestern Brazil

Nymphs and adults of the lace bug (Hemiptera: Tingidae) have been found in cassava crops (Manihot esculenta) in Mato Grosso do Sul State, Brazil. The insects were collected in the field and taken to the laboratory where they were identified based on some morphological traits of the species Vatiga manihotae (Drake) and V. illudens (Drake), which are first reported in the aforementioned state.

Ocorrência de Aleurothrixus aepim (Goeldi, 1886) em mandioca na região Oeste do Paraná

This paper work recorded the occurrence of Aleurothixus aepim Goeldi in cassava plants in the West of Parana, Brazil. The species was first found in February, 2009, in an experimental area at Universidade Estadual do Oeste do Parana (UNIOESTE), in cassava leaves of the white starch variety. The samples were collected by gathering leaves infested with whitefly nymphs, which are characterized for presenting body coated by white waxy filaments. The material was preserved in 70% ethanol, in glass bottles, and sent for identification. New outbreaks have been recorded in the beginning of 2010 and 2011 in different rural properties located in the city of Marechal Candido Rondon. However, the precise cause of the occurence of A. aepim in this region is not completely clear. In the other production regions of the State, this species has not yet been detected.

Adequação do hospedeiro e parâmetros relacionados à aptidão de Cotesia glomerata L. (Hymenoptera: Braconidae) em diferentes ínstares de Ascia monuste orseis Godart (Lepidoptera: Pieridae)

The study aimed to adapt the instar of host Ascia monuste orseis to the parasitism of Cotesia glomerata and evaluate the parasitoid performance. Females of C. glomerata were exposed to 2nd, 3rd, 4th and 5th instars larvae of A. monuste orseis , allowing parasitism for two hours. Subsequently, the development of caterpillars that were fed with leaf sections of kale was monitored. The duration of each caterpillar instar, the weight of four days-old pupae, the percentage of parasitized caterpillars and mortality were assessed. Despite parasitoids, the following parameters were assessed: percentage of parasitism; number of parasitoids per host; percentage of emergence, sex ratio; average weight of the pupae, number of parasitoids per caterpillar; period egg-pupae; pupal period; and period egg-adult. The results indicated that the second instar of host A. monuste oreseis is the most suitable for the parasitism of C. glomerata for providing highest percentage of parasitism and a larger number of offspring per host.

External morphology of the immature stages of Vatiga manihotae (Hemiptera: Tingidae) with comments on ontogenesis

Abstract Vatiga (Hemiptera: Tingidae) species show preference for Cassava plants (Euphorbiaceae: Manihot), an important food source in the American tropics. Infestations of Cassava by Vatiga can cause serious harvest losses. Information on immature stages morphology can aid in early identifications of crop pests and provide data for use in phylogenetic analyses; thus, we describe and illustrate the external morphology of all life stages of Vatiga manihotae using optical and scanning electron microscopies. Eggs are laid inserted in the leaf blade, are whitish and oblong, with smooth chorion. In the larvae, the tegument is covered by hemispherical projections, which remain the same and become denser through ontogenesis. Dorsal surface of head and lateral margins of body with tubercles; from the second through the fifth instars the cephalic and lateral tubercles maintain the same structure, only adding setae along its surfaces. The cephalic tubercles of V. manihotae nymphs are more complex than those of the adults, as on the latter the cephalic tubercles lack setae. As suggested by literature, our discoveries fit the intermediate clades scenario of the ontogenetic pathway in which larvae have outgrowths and adults are simple, suggesting that brood protection is absent and larval protection by secretions may be present.

Ocorrência natural de Beauveria bassiana (Bals.) Vuill. (Moniliales: Moniliaceae) e patogenicidade sobre Protortonia navesi Fonseca (Hemiptera: Monophlebiidae) na cultura da mandioca, em Marechal Cândido Rondon, Paraná

The objective of this study was to record the first natural occurrence and pathogenicity of the association between Beauveria bassiana and Protortonia navesi in the cassava crop. Infected P. navesi nymphs and adults were collected in samples fortnightly in the Agronomic Institute of Parana, in Marechal Cândido Rondon, from January to December 2012. Samples were analyzed at the Laboratory of Agricultural Biotechnology. The entomopathogenic fungus was isolated from corpses using selective oatmeal culture medium, and multiplied for sporulation being identified as Beauveria bassiana (Bals.) Vuill. The fungus was stored in the Collection of Entomopathogenic Fungi Laboratory of Agricultural Biotechnology, identified as Unioeste 78. To prove the pathogenicity of the found isolate, bioassays were performed following the postulate of Koch, the fungi suspension was sprayed (109conidios mL), on nymphs and adults of P. navesiobtained from laboratory rearing. After 10 days of incubation there was 18% mortality confirmed, being considered low actgivity on mealybugs Protortonia.