嗜菌异小杆线虫H06品系对红棕象甲解毒酶活性影响

为阐明嗜菌异小杆线虫H06品系对红棕象甲的作用机制,采用生物化学测定法研究了嗜菌异小杆线虫H06品系线虫接种红棕象甲幼虫后,对红棕象甲体内羧酸酯酶(CarE)、乙酰胆碱酯酶(AChE)和谷胱甘肽-S-转移酶(GST)活性的影响。结果表明,经嗜菌异小杆线虫H06品系侵染后,红棕象甲幼虫体内3种酶的活力均呈现先上升,后下降的趋势。其中处理后36 h,CarE活性比对照组升高43.15%,之后酶活力缓慢下降,至72 h时处理组酶活力比对照组降低29.55%;处理后36 h,AChE的酶活力比对照组增加79.42%,之后活力出现下降,至处理后72 h活力与对照组相比降低17.51%;对GST活力影响中,处理后12、24、36、48、60 h和72 h,红棕象甲GST酶活力水平与对照相比分别增加99.96%、62.28%、142.61%、145.81%、103.10%和38.39%。由此可知嗜菌异小杆线虫H06品系可通过干扰红棕象甲幼虫体内解毒酶的活性,从而达到对该虫致死的效果。

Effect of Zinc Sulfate against the Red Palm Weevil Rhynchophorus ferrugineus with Reference to Their Histological Changes on the Larval Midgut and Adult Reproductive System

The red palm weevil Rhynchophorusferrugineus is the most important insect pest for the date palm trees in the Middle East and Gulf states. Zinc sulfate （ZnSOa＇H20） was toxicologically, biologically and physiologically evaluated as insect development disruptors against the RPW. LCs0 of Zinc sulfate against 10 days old larvae was 0.566%, 3% concentration inhibited the larvae from feeding. LCs0 concentration of zinc sulfate solution was capable to disrupting growth, development and reproduction of R. ferrugineus. Growth and development disruptions are resulted from larval feeding on the treated diet that causing percentage of mortality rate, retardation in larval and pupal duration, percentage of pupation, adults emergence, reduction in deposited eggs that laid by the resulting adults and in the egg fertility. The study further reveals that Zinc sulfate effects on histological structure of epithelial cells of the larval midgut including separation and elongation of their cells, rupture in the peritrophic membrane and in some microvilli and some degeneration of the surrounding muscles. Histological changes also was observed on the adults ovary, in this way, disrupt female gamete production through their action on the accumulation of yolk granules （vitellogenesis） and follicular epithelial cells. Disruption of male gamete production was detected by disorganized of testicular cysts and depopulation of these cysts in addition to degeneration in germ cells. Zinc sulfate may be used among other control methods by injection into the tree trunk or as fertilizer around the tree roots which in turn may have an indirect effect for controlling the RPW.

An Advanced Catch-and-Release Trap for Controlling the Red Palm Weevil

The aim of the research was to develop a catch-and-release trap for monitoring and controlling RPW （Rhynchophorus ferrugineus, red palm weevil）. The RPW insects were attracted through the use of an aggregation pheromone located into a dispenser inside the trap. The RPW adults entered through an entrance door into a sterilization room where they were sprayed with a solution containing the chemical sterilizer product ＂lufenuron＂. The adults were then forced to move into a contamination room where it was present a wet media containing spores and hyphae of Metarhizium anisopliae and spores and crystalline insecticidal proteins of Bacillus thuringensis. The sterilized and infected RPW adults were counted and released into the environment where they reached new palms and join natural populations of RPW. Preliminary experiments showed that the catch-and-release trap was able to reduce the fertility of RPW adults and to increase their mortality after contamination with entomopathogens. Moreover, the infected RPW adults were able to infect untreated RPW larvae leading to a larvae mortality of 93% within 30 days. In conclusion, the advanced catch-and-release trap represents a safe and effective tool to monitor and control the population of RPW pest without environmental pollution and risks for human health.