ABSTRACT: Asian citrus psyllid, Diaphorina citri, is considered the most important citrus pest worldwide, as it transmits Huanglongbing – serious citrus disease. New efficient and sustainable strategies to control this pest have been investigated and the use of entomopathogenic fungi has become a promising alternative. The objective of this study was to evaluate the effects of adjuvants a) Tween 80 at 0.01 % (v/v); b) Silwet L77 at 0.025 % (v/v) and c) KBRAdj at 0.075 % (v/v) on adhesion, germination and pathogenicity of Isaria fumosorosea ESALQ-1296(5 × 106 conidia mL–1). Female adults of D. citri used in this experiment were sprayed on Citrus limonia seedlings. The sprayed insects were analyzed through scanning electron microscopy (SEM) to identify the most susceptible integument regions for fungus attachment and the effect of adjuvants used. In the pathogenicity test, adjuvants Silwet L77 and KBRAdj presented a higher efficiency than Tween 80. Fungi adhered predominantly to the ventral posterior (abdomen) region in comparison with the dorsal anterior (thorax) region. In addition, adjuvants Silwet L77 and KBRAdj presented faster germination (< 48 h) of I. fumosorosea spores when compared to Tween 80 (> 72 h). Conidial germination in the dorsal part of the thorax of the insects was observed only with adjuvant KBRAdj 72 h post inoculation.

O efeito de oito fungicidas e doze inseticidas, utilizados nas culturas de alface e crisântemo, foi avaliado in vitro sobre os fungos entomopatogênicos Beauveria bassiana (Bals.) Vuill., Metarhizium anisopliae (Metsch.) Sorok., Paecilomyces fumosoroseus (Wise) (Holm ex SF Gray) e Verticillium lecanii (Zimmerman). Os produtos foram colocados em placas de Petri contendo meio de cultura (BDA), nas concentrações recomendadas para aplicação em campo. Após a inoculação dos fungos, as placas foram incubadas em sala climatizada a 25±1°C, fotofase de 12h e umidade relativa de 70±10%. Foram avaliados o diâmetro médio das colônias e o número de conídios produzidos após um período de incubação variável para cada fungo estudado. Os inseticidas tiametoxam e imidaclopride foram compatíveis com todos os fungos estudados. Por outro lado, óxido cuproso, iprodione, paratiom metílico, tebuconazole, metalaxil, mancozebe, folpete, fenpropatrina e tetraconazole inibiram o crescimento dos fungos, sendo classificados como produtos tóxicos ou muito tóxicos aos entomopatógenos.

The effect of eight fungicides and twelve insecticides used in lettuce and chrysanthemum crops, was evaluated on the fungi Beauveria bassiana (Bals.) Vuill., Metarhizium anisopliae (Metsch.) Sorok., Paecilomyces fumosoroseus (Wise) (Holm ex SF Gray) and Verticillium lecanii (Zimmerman) through in vitro tests. The products were added to petri dishes containing culture medium (PDA), according to the concentrations recommended for application in field. After the inoculation of the fungi, the plates were incubate at 25±1°C, 12h fotophase and 70±10% relative humidity. The mean diameter of colonies and the number of conidia produced after a variable period of incubation for each studied fungus were evaluated. The insecticides thiametoxan and imidacloprid were compatible with all the fungi studied. On the other hand, cuprous oxide, iprodione, methyl parathion, tebuconazol, metalaxil, mancozeb, folpet, fenpropathrin and tetraconazol inhibited the growth of the fungi, being classified as toxicant or very toxicant products to the entomopathogens.