New Host Plant Records for the Stink Bug Piezodorus guildinii in Florida (Hemiptera: Pentatomidae)

Abstract

Piezodorus guildinii (Westwood) is a neotropical pentatomid that occurs from the southern United States to Argentina. This species is a serious pest of soybean throughout South America, particularly in Brazil (summarized in Panizzi and Slansky 1985a). It was commonly found on soybean during 1983 in north-central Florida (A. R. Panizzi, unpublished observations), where its abundance in the past few years seems to have increased (Menezes 1981), suggesting that it potentially could become a serious soybean pest in Florida. P. guildinii is polyphagous; reported host plants include a number of wild and cultivated species, many of which are legumes (e.g., alfalfa, lentil, green bean and soybean; summarized in Panizzi and Slansky 1985a). However, some of these plants may only provide a substrate for resting or refuge and may not actually be host plants. We found eggs, nymphs and adults of P. guildinii on 3 apparently unreported host plants during November and December, 1983 in Alachua County, Florida. These plants were: Indigofera hirsuta L., Crotaclaria lanceolata E. Mey., and Crotalaria brevidens Benth. On the first two species, egg masses were observed on pods; nymphs (lst through 5th instars) and adults were found most frequently feeding and/or basking on pods. Late instar nymphs and adults would hide among the pods when disturbed, and as many as 20 individuals were found on a single host plant. On the third species, only one 5th instar nymph was found (feeding on a pod). Subsequent research on adult biology of P. guildinii (Panizzi and Slansky 1985b) indicated that pods of I. hirsuta, and to a lesser extent C. lanceolata (C. brevidens was not included in our study) allow early oviposition and increased fecundity compared to adults fed raw shelled peanuts, dry soybean seeds or green (snap) beans. We successfully reared nymphs on I. hirsuta pods but high mortality occurred when reared on green beans (the latter are commonly used as a suitable laboratory food for another polyphagous stink bug, Nezara viridula (L.); Harris and Todd 1980). The broad host plant range of P. guildinii indicates that a number of wild plant species could serve to maintain its populations when cultivated host plants are unavailable, and provide sources from which colonization of soybean and other cultivated hosts occurs. In Brazil, P. guildinii has been recorded on an unspecified species of Crotalaria (Monte 1939). In Colombia,