Lygus hesperus is an important pest on different crops including cotton and alfalfa in Western US. It is polyphagous, feeding on 117 non-crop plants and over 25 cultivated plants. In winter and early spring, Lygus populations are found on alfalfa, and on different weeds as shepherd's purse, common groundsel, annual ragweed, and pigweed. As plants senesce or are harvested, Lygus migrate into nearby susceptible crops such as cotton. Anaphes iole Girault is the most commonly encountered parasitoid of Lygus eggs in the U.S. This parasitoid attacks Lygus eggs in a variety of crops, but its efficacy appears to vary with the plant species in which host eggs are located. i>Lygus populations are known to reach higher numbers in alfalfa fields compared to cotton. Moreover, interplanting alfalfa in cotton fields has been suggested to reduce Lygus populations. However, studies have not been conducted evaluating host habitat preference of Anaphes iole. Therefore, the objective of this study was to evaluate attraction and parasitism of L. hesperus eggs by A. iole on different plants in choice experiments. Shepherd's purse, common groundsel, annual ragweed, pigweed and alfalfa plants were placed in cages containing cotton plants, all infested with Lygus eggs. Female parasitoids were released in each cage and allowed to search and parasitize hosts for 24hs. The number of Lygus nymphs or Anaphes adults emerging from each plant were recorded, and percentages of parasitism were calculated. In addition, Anaphes preference towards different host plants related to cotton are discussed.
Species 1: Heteroptera Miridae Lygus hesperus (Western tarnished plant bug)
Species 2: Hymenoptera Mymaridae Anaphes iole
Keywords: Habitat preference, Anaphes parasitism
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