Sub-lethal effects of a copper sulfate fungicide on development and reproduction in three coccinellid species

Abstract

Copper-based fungicides reliably control various foliar diseases in citrus production, although they are suspected to exacerbate mite problems through various mechanisms. Studies have shown negative effects of various copper formulations on entomopathogenic fungi, nematodes, and parasitoids, but few have sought to measure its impact on the biology of predatory insects. We exposed the larvae of three species of ladybeetle (Coleoptera: Coccinellidae) to field rates of copper sulfate in combination with petroleum oil, a formulation commonly applied in Florida citrus. First instar larvae of Curinus coeruleus Mulsant, Harmonia axyridis Pallas, and Olla v-nigrum Mulsant received a 24 h exposure to residues on Petri dishes, and another 24 h exposure in the third instar. Treated larvae of all three species survived to adulthood at the same rate as control larvae, but larvae of O. v-nigrum experienced a significant increase in developmental time. Female adults of C. coeruleus and H. axyridis receiving copper sulfate exposures as larvae did not differ from control adults in pre-reproductive period, fecundity or fertility over ten days of reproduction. Treated O. v-nigrum females had significantly longer pre-reproductive periods than control females and laid significantly fewer eggs, although egg fertility was equivalent. We conclude that copper-sulfate fungicides are unlikely to disrupt biological control processes in citrus groves that are mediated by these coccinellid beetles.

Age-dependent fecundity of Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) with sublethal doses of gammacyhalothrin

“…The highest doses of gammacyhalothrin reduced the preoviposition, oviposition and postoviposition periods of P. nigrispinus, which was also found for S. cincticeps with low dosages of permethrin (5.74x10 -3 and 5.74x10 -2 ppb) . However, the pre-reproductive period of three coccinelid species were not affected by the exposure to copper sulfate fungicide (Michaud and Grant, 2003). The oviposition period of the P. maculiventris females was not affected by the sublethal doses of diflubenzuron and pyriproxyfen (De Clercq et al, 1995) found for other Pentatomidae predators Magalhães et al, 2002).…”

“…The spined soldier bug Podisus maculiventris (Say) (Heteroptera: Pentatomidae) had a longer fourth and fifth instar when exposed to sublethal doses of the insect growth regulator teflubenzuron (Mohaghegh et al, 2000). Olla v-nigrum (Mulsant) (Coleoptera: Coccinellidae) showed a longer larva stage after 24 h exposed to the residues of Copper Sulphate and Petroleum Oil (Michaud and Grant, 2003). Hormesis is advantageous to individuals when resources are initially and principally allocated to fix problems caused by immediate damage (Calabrese and Baldwin, 2002).…”

“…The apparent low survival rates of these insects in the treated and untreated plots as well as the differences in the level of susceptibility of specific predators to chemical insecticides are important factors. The survival of three coccinelid species was similar to the control after exposure to sublethal doses of a copper sulfate fungicide (Michaud and Grant, 2003) but the number of individuals of G. punctipes was reduced in the field by the sublethal effects of the S-1812 (a dihalopropenytoxy benzene insecticide) (Tillman and Mulroney, 2000). The higher mortality of P. nigrispinus nymphs with the highest doses of gammacyhalothrin could be explained by the different cuticular penetration rate in nymphs and adults of P. nigrispinus.…”

“…The effects of insecticides on fecundity and reproduction of natural enemies depends on the species. O. vnigrum females laid fewer eggs when treated with copper sulphate in the larvae stage (Michaud and Grant, 2003) and sublethal doses of azadiracthin reduced the number of fertile eggs of Chrysoperla carnea (Neuroptera: Chrysopidae). The number of eggs of P. maculiventris females per day was similar when they were exposed to sublethal doses of insecticides (De Clercq et al, 1995).…”

Genetic Engineering and Sustainable Crop Disease Management: Opportunities for Case-by-Case Decision-Making

“…Pesticide use raises significant concerns over impacts on health [2][3][4][5][6][7] and the environment [8][9][10][11][12]. Furthermore, we cannot address the challenges to sustainability posed by synthetic pesticides by simply switching to the application of natural pesticides, because the same concerns apply to them [12][13][14][15][16][17][18][19].…”