Impact of five insecticides used to control citrus pests on the parasitoid Ageniaspis citricola Longvinovskaya (Hymenoptera: Encyrtidae).

The parasitoid Ageniaspis citricola Longvnovskaya is a main biological control agent of the citrus leafminer Phyllocnistis citrella Stainton, an insect pest that causes considerable damage to citrus worldwide. However, the use of pesticides to control arthropod pests can reduce the effectiveness of parasitoids and disrupt integrated pest management in citrus groves. This study evaluated the impact on A. citricola of five insecticides that are used to control arthropod pests in citrus. Our results indicated that imidacloprid, chlorpyrifos, bifenthrin and ß-cyfluthrin were harmful (mortality >89 %) to A. citricola adults; whereas abamectin did not cause significant mortality and was considered harmless to the parasitoid. In addition to causing high mortality, imidacloprid and bifenthrin were considered moderately persistent, because they caused <25 % mortality to 17 and 24 days after spraying (DAS), respectively. Chlorpyrifos and ß-cyfluthrin were considered slightly persistent (mortality <25 %, 7 DAS). Although abamectin was considered harmless to A. citricola adults, had a short life (mortality <25 %, 3 DAS), and did not significantly affect the parasitism rate, the number and viability of pupae, or the longevity of A. citricola, this insecticide significantly reduced the proportion of females in the progeny compared to the control treatment. Therefore, semi-field and field studies that consider demographic parameters are needed to evaluate the impacts of these insecticides on the A. citricola parasitoid.

Impact of insect growth regulators on the predator Ceraeochrysa cincta (Schneider) (Neuroptera: Chrysopidae).

The generalist predator Ceraeochrysa cincta (Schneider) (Neuroptera: Chrysopidae) is an important biological control agent of several arthropod pests in different agroecosystems. This study assessed the lethal and sublethal effects of six insect growth regulators sprayed on first-instar larvae of C. cincta. Lufenuron and diflubenzuron were highly harmful to first-instar larvae of C. cincta, causing 100 % of mortality before they reached the second instar. Buprofezin caused ~25 % mortality of the larvae and considerably reduced the fecundity and longevity of the insects, but substantially increased the proportion of females in the surviving population of C. cincta. Methoxyfenozide and tebufenozide did not affect the duration and survival of the immature stages, but methoxyfenozide significantly reduced the fecundity and longevity of the insects. Pyriproxyfen reduced the survival of the larval stage by 19.5 %, but did not affect the development, survival and reproduction of the surviving individuals. Based on reduction coefficient, the insecticides diflubenzuron and lufenuron were considered harmful to C. cincta, whereas buprofezin and methoxyfenozide were slightly harmful and tebufenozide and pyriproxyfen were harmless. The estimation of life-table parameters indicated that buprofezin and methoxyfenozide significantly reduced the R o , r and λ of C. cincta, whereas pyriproxyfen and tebufenozide caused no adverse effect on population parameters, indicating that these insecticides could be suitable for use in pest management programs towards the conservation and population increase of the predator in agroecosystems. However, more studies should be conducted to evaluate the compatibility of these insecticides with the predator C. cincta under semi-field and field conditions.

Are the Pupae and Eggs of the Lacewing Ceraeochrysa cubana (Neuroptera: Chrysopidae) Tolerant to Insecticides?

The tolerance of Ceraeochrysa cubana (Hagen) pupae and eggs to 11 insecticides was evaluated under laboratory conditions, based on lethal and sublethal effects. Eggs at three ages (≤24-h-old, 48- to 72-h-old, and 96- to 120-h-old) and pupae at ≤48-h-old were used. All the insecticides were considered harmless when applied at the pupal stage. Phosmet and pyriproxyfen insecticides were considered harmless to eggs irrespective of the age. Esfenvalerate was harmless to eggs at the ages of ≤24-h-old and 48- to 72-h-old. Imidacloprid SC and azadirachtin were harmless to eggs at ages of 48- to 72-h-old and 96- to 120-h-old, and thiamethoxam was only harmless to eggs at 96- to 120-h-old of age. In contrast, chlorpyrifos and malathion were harmful to eggs at the age of 96- to 120-h-old, and imidacloprid WG was slightly harmful to the three egg ages evaluated. Lambda-cyhalothrin + chlorantraniliprole and lambda-cyhalothrin + thiamethoxam were slightly and/or moderately harmful to all egg ages evaluated. Based on the life table parameters, the insecticides thiamethoxam, imidacloprid SC, phosmet, pyriproxyfen, and azadirachtin did not affect the net rate of reproduction (Ro) of C. cubana. Lambda-cyhalothrin + chlorantraniliprole decreased the Ro and increased the population doubling time (Td) independently of the egg ages evaluated. Therefore, the insecticides pyriproxyfen and phosmet are compatible with eggs of the predator C. cubana, but other insecticides should be evaluated under field conditions to verify their effects on the predator.