Negative effect of fungicides used in practical hop protection against Downy mildew (Pseudoperonospora humuli) on aphidophagous coccinellids Propylea quatuordecimpunctata L
2013
Vostrel, J.
Still increasing attention has been paid to the development of IPM systems within EU countries. Natural enemies play a very important role in these systems. Therefore, it is necessary to use only such pesticides, whose harmfulness is generally lower and acceptable. Downy mildew (Pseudoperonospora humuli) is commonly controlled by fungicides applied during the season. Nevertheless, at that time numerous aphidophagous predators, especially coccinellids are present on leaves of the treated plants feeding on aphids. Ladybird Propylea quatuordecimpunctata L. belongs to the most important species attacking damson-hop aphid (Phorodon humuli Schrank). Fungicides, which are in current use, were tested on eggs, larvae, pupae and adults of this ladybird species to determine their real effect and convenience of their inclusion within IPM systems. The fungicides tested in the bioassays increased the mortality rate of each developmental stage of P. quatuordecimpunctata. Adults of coccinellids were more resistant to the fungicides than the other developmental stages. Very low susceptibility was found out after treatment with azoxystrobin. High tolerance of adults was confirmed also in the other tested fungicides. Eggs and larvae were generally more susceptible than adults. Azoxystrobin again showed the lower toxicity and its convenience for IPM system as the mortality of eggs as well as larvae was the lowest. On the contrary, copper fungicides showed commonly higher mortality.
اظهر المزيد [+] اقل [-]الكلمات المفتاحية الخاصة بالمكنز الزراعي (أجروفوك)
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