Status of pigeonpea as an alternative host of Piezodorus guildinii (Hemiptera : Pentatomidae), a pest of soybean

Pigeonpea, Cajanus cajan (L.) Millsp. (Leguminosae), was found hosting Piez odorus guildinii (Westwood) (Hemiptera: Pentatomidae) in Parana State, Braz il. In the laboratory, nymphs performed better on immature pods of soybean, Glycine max (L.) Merrill (Leguminosae), than on immature pods of pigeonpea . Although nymphs required similar time to complete development, and attain ed similar weights at adult emergence, mortality was much lower on soybean (57.7%) than on pigeonpea (94.4%). Adult P. guildinii also performed better on soybean than on pigeonpea. Females and males showed similar longevity o n both foods, but 34.5% of females oviposited on soybean compared to 10.3% on pigeonpea, with an oviposition delay of 26 days on pigeonpea compared to soybean. Fecundity (eggs/females) was 6.5x greater on soybean than on pige onpea, and adult body weight gain after 14 and 28 days was 13-23% greater o n soybean than on pigeonpea. P.guildinii also showed greater feeding activi ty on, and greater feeding preference for, soybean than pigeonpea. Bugs col onized soybean during summer and early autumn (January-March), and pigeonpe a during autumn, early winter (April-July), and spring (October-November). These results indicate that pigeonpea, although a less preferred and less s uitable plant food source of P. guildinii in Brazil, plays an important rol e to the bug's life history by serving as a temporary host.