Functional Response and Control Potential of Orius sauteri (Hemiptera: Anthocoridae) on Tea Thrips (Dendrothrips minowai Priesner)

This study aimed to clarify the functional response and control potential of O. sauteri in relation to tea thrips. The functional response, interference response, and control potential of O. sauteri on adult tea thrips, in different insect stages and environment temperatures, were studied. The results showed that the predation of O. sauteri against tea thrips was positively correlated with prey density, while the effects of searching for O. sauteri on the adult tea thrips were negatively correlated with prey density. The predation effects of O. sauteri on tea thrips were also influenced by prey density, which indicated that there was an intra-specific interference response from predators to tea thrips. The population density of tea thrips was significantly decreased, and O. sauteri showed a remarkable ability to control them when the benefit-to-harm ratio was 3:100.

Selection of suitable predatory mites against, Panonychus citri (McGregor) (Acari: Tetranychidae) using relative control potential metrics and functional response

Background Selection of suitable predators for the control of the spider mite, Panonychus citri is always a challenge due to the lack of their reliable predicted efficacy. In this laboratory study, biological control potential of Neoseiulus californicus, N. cucumeris and Scapulaseius newsami, against P. citri using the “Relative Control Potential” (RCP) metric to compare their efficacies was evaluated. The functional response type was determined at different prey densities (after 24 h). Results The type II functional responses were observed from all the tested predators feeding on 3 different life stages of P. citri, except N. cucumeris, which was fed only on eggs. All predatory mites preferred eggs of P. citri with a higher attack rate (1.397) in N. cucumeris, followed by N. californicus (1.238) and S. newsami (0.975). Handling time was also lower in N. cucumeris than other mites, with a trend as: for N. cucumeris, eggs > adults > immature stages; for N. californicus, immature stages > eggs > adults, while for S. newsami, eggs > immature stages > adults. The integration of greenhouse abundance and fecundity (%) data resulted in a higher RCP for N. cucumeris than other predators. Conclusion Neoseiulus cucumeris was selected as the most suitable predatory mite for the control of P. citri with a higher RCP and potential to maximum reproduction. S. newsami, which was used for the first time, gave almost similar results compared to N. californicus but with lower efficacy.

Effect of dietary prebiotic inulin and probiotic Bacillus subtilis and Lactobacillus sp., on the intestinal microbiota of white shrimp Litopenaeus vannamei

Juvenile Litopenaeus vannamei (1.05 ± 0.1 g) were fed during 4-week with four experimental diets: control (Ctrl), inulin as prebiotic (5 g kg-1) (Pre), Bacillus subtilis and Lactobacillus sp. as probiotic (1 x 105 CFU g-1) (Pro), and a mix of inulin + B. subtilis and Lactobacillus sp. (5 g kg-1 + 1 x 105 CFU g-1) (Syn). Shrimps fed Syn diet showed significantly better feed utilization and higher growth than those in control diet (P < 0.05). The probiotic employed induced higher intestinal bacterial richness, whereas inulin in feed induced higher bacterial diversity in shrimp intestine. The most dominant bacterial phylum in the shrimp intestine among treatments was Proteobacteria with abundance ranging between 80 and 84 %. Prebiotic diet (Pre) increased relative abundance of Firmicutes in shrimp intestine (2 %) compared to the rest of the treatments (0.6 %). Nevertheless, when probiotics were included in the feed (Pro and Syn), a reduction between 3 and 13 % in the relative abundance of Vibrio sp. in shrimp intestine was observed respect to the control treatment, which represent an advantage to control potential pathogens of this genus.