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Cotton mealybug,Phenacoccus solenopsisTinsley is an important polyphagous insect pest and causes severe losses to different crops worldwide. In the current study, we investigated the effect of different host plants, such asCaesalpinia pulcherrima,Plumeria rubra, Anthurium andraeanum, Jasminum sambac, andHibiscus rosasinensis, on the biological parameters ofP. solenopsis. The survival rate from crawler to adult, female nymphal duration, development time from crawler to female adult, and female adult weight were significantly different on the different hosts. Male nymphal duration, development time from crawler to male adult, pupal weight, emergence rate of male adults, and mean relative growth rate for male were similar on all the tested host plants. Pupal duration and generation time of male and female onH. rosasinensiswere significantly shorter than on the other hosts. Adult male and femaleP. solenopsislongevity was significantly shorter onH. rosasinensiscompared to other hosts. The fecundity was lower onC. pulcherrimaandA. andraeanumand hatchability was lower onC. pulcherrimathan on the other hosts. The net reproductive rate, the intrinsic rate of natural increase, and biotic potential and mean relative growth rate for female ofP. solenopsiswere significantly different on the tested hosts. Our results point to the role of host plants in increasing the populations ofP. solenopsisand could help to design cultural management strategies.

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Culex quinquefasciatus Say is an important pest species and a vector of multiple pathogens. Insecticide applications are necessary for the effective control of mosquitoes. In the current study, a laboratory population of Cx. quinquefasciatus was exposed to chlorpyrifos for 15 consecutive generations and then assessed for the changes in detoxification enzyme activities before and after exposure to Metarhizium anisopliae (Metschn.) Sorokin and Beauveria bassiana (Bals.) Vuill. during 14th–15th generations. Activities of acetylcholinesterase (AChE), glutathione S-transferase (GST), esterase (EST), acid phosphatases (ACP), and alkaline phosphatases (ALP) were increased in the chlorpyrifos-selected (Chlor-SEL) population in relation to an unselected (Un-SEL) population. The resistance ratio of Chlor-SEL 15th generation (G15) was increased 3,583-fold against first generation (G1) and 6,026-fold against the Un-SEL population. The results depicted maximum activities of ACP (83.48), ALP (65.54), GST (13.047), EST (10.42), and AChE (4.86) μmol/min of mg/ml protein at G15 after consecutive chlorpyrifos applications. The Chlor-SEL populations at G14–G15 were treated with different concentrations of M. anisopliae and B. bassiana for possible suppression of enzymatic activities. Activities of ACP were suppressed to 24.22 μmol/min of mg/ml protein at G15 when exposed to B. bassiana and 22.40 μmol/min of mg/ml protein at G14 after exposure to M. anisopliae. The suppression of detoxification enzymes by application of fungi in resistant population of Cx. quinquefasciatus will aid in the mosquito’s management programs.

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Asiatic citrus psylla, Diaphorina citri, Kuwayama (Hemiptera: Liviidae) is an economic pest of citrus groves and a vector of the bacterium, Candidatus Liberibacter spp., one of the causative agents of citrus greening. In order to estimate the infectivity of six different isolates of Beauveria bassiana, Metarhizium anisopliae and Isaria fumosorosea, fungal bioassay was performed on the adults of D. citri. Adults of D. citri were treated individually with 1 × 10 5 , 1 × 10 6 , 1 × 10 7 , 1 × 10 8 , 2 × 10 8 spores/mL fungal concentrations by the immersion method. Subsequent to fungal bioassay, treated D. citri were used to determine the levels of esterase and glutathione S-transferases (GST) enzymes over a period of 3-7 days. The mortality results suggest that I. fumosorosea isolates (If-02) caused 82.2% mortality on the seventh day of treatment. However, B. bassiana isolate (Bb-08) with lowest LC 50 (1.4 × 10 7 spores/mL) proved to be highest potential isolate against D. citri. Biochemical determination of esterase and GST activity assay showed significant differences in activities after infection of fungi. Significantly high activity of esterase was observed by Bb-01 (27.0 unit per mg protein) on the seventh day, while Ma-11.1 and If-2.3 (16.9 and 36.3 unit per mg protein) on the third day post treatment. However, maximum GST's activity was showen by isolates Bb-08,Ma-M 2 and If-2.3 (37.6, 1.40 and 10.9 unit per mg protein) on the third day. The current investigation will help to explore the relations between the insect defense system and entomopathogenic fungi. Moreover, the determination of enzymatic activities will be useful for selecting the most pathogenic isolates.