Influence of copper oxide fungicide on populations of Brevipalpus phoenicis (Geijskes)

Abstract

Field and laboratory experiments were carried out to verify the hypothesis whether cupric fungicides would cause an increase in populations of the leprosis mite, Brevipalpus phoenicis (Geijskes). In the laboratory experiment each seedling of the sweet orange (Citrus sinensis) was treated with different doses of copper oxide (0, 21, 42, 84 and 168g i.a. /100 liters of water) and received 15 females of B. phoenicis and kept at 25ºC. Counting of the mites’s eggs, larvae, nymphs and adults was undertaken after 48 days. The field experiment was conducted in a Natal variety citrus orchard. The treatments were the same used in the laboratory experiment and the fungicide was applied with a pistol pulverizer. After 40 and 60 days fifteen fruits were sampled in each batch. Both experiments were designed in randomized blocks of 5 treatments and 5 repetitions in the field experiment and 6 in the lab one. Results of both experiments showed no significant difference between treatments. No correlation between doses of fungicide and mite population was verified. The results of the investigation led to the conclusion that the different doses of copper oxide did not cause a significant increase of B. phoenicis population, in both field and laboratory experiments.