Effects of some fungicides on Isaria farinosa, and in vitro growth and infection rate on Planococcus citri

Abstract

The effects of some fungicides used against citrus diseases, on mycelial growth and conidial germination of Isaria farinosa (Holmsk.) Fries [Sordariomycetes: Hypocreales] and also on the pathogenicity of the fungus on citrus mealybug, Planococcus citri (Risso), were determined. Systemic fungicides such as tebuconazole, penconazole and nuarimol were the most effective as regards both conidial germination and mycelial growth. Protective fungicides such as captan, chlorothalonil, mancozeb and propineb inhibited conidial germination at between 1 and 5 μg ml −1 concentration, but captan, chlorothalonil and propineb did not inhibit the mycelial growth at 5,000 μg ml −1 . Mancozeb inhibited mycelial growth between 2,500 and 5,000 μg ml −1 . Sulphur and copper oxychloride did not inhibit the fungus even at very high concentrations. Sulphur, copper oxychloride, fosetyl-al, chlorothalonil and carbendazim did not decrease the mortality percentage caused by I. farinosa. Tebuconazole, penconazole and mancozeb were the most effective and respectively reduced the mortality from 83% to 33%, 28% and 30% in the ovisacs, from 81% to 29%, 27% and 29% in the 1st instar larvae, and from 84% to 34% in the adult females.

Laboratory assay of the effectiveness of the entomopathogenic fungusIsaria farinosa(Holmsk.) Fries (Sordariomycetes: Hypocreales) against the vine mealybugPlanococcus ficus(Signoret) (Hemiptera: Pseudococcidae), even under the use of fungicides

“…Sulphur, copper oxychloride, fosetyl-Al and chlorothalonil were found to be the most compatible fungicides with the entomopathogenic fungus. These results are parallel with our previous study (Demirci et al 2011b).…”

“…There are some studies about the in vitro effects of fungicides on entomopathogenic fungi (Olmert & Kenneth 1974;Zimmermann 1975;Todorova et al 1998;Butters et al 2003;Sapieha-Waszkiewicz et al 2004;Demirci & Denizhan 2010;Demirci et al 2011b). A few studies were conducted on the effects of fungicides on the pathogenic activity of entomopathogens (Latteur & Jensen 2002;Demirci et al 2011b).…”

“…A few studies were conducted on the effects of fungicides on the pathogenic activity of entomopathogens (Latteur & Jensen 2002;Demirci et al 2011b).…”

Aislamiento, identificación y patogenicidad de Hirsutella en Planococcus citri.

“…El protocolo utilizado se basó parcialmente en el estudio desarrollado por Demirci et al (2011a), dado que el bioensayo se enfocó en estudiar el efecto patogénico del hongo sobre adultos de P. citri. Para ello se diluyó un gramo de micelio en 5 ml de agua destilada estéril y se agitó por dos minutos en vórtex.…”

“…Los hongos entomopatógenos como Hirsutella son capaces de sobrevivir en la naturaleza y pueden ocasionar infecciones repetitivas, siempre y cuando se tomen las precauciones pertinentes en campos con aplicaciones previas de fungicidas (Demirci et al, 2011a).…”