PENTANOIC ACID ATTRACTS OLCELLA-PARVA (ADAMS) (DIPTERA, CHLOROPIDAE) IN COLORADO CORN FIELDS

AS part of a study of attractants for western corn rootworm (Diabrotic a virgifera virgifera LeConte) adults, short-chain free fatty acids we re placed on yellow sticky traps in a Colorado corn field. Olcella paw a (Adams) were attracted to traps baited with 10 or 100 mg pentanoic a cid. Hexanoic acid (10 and 100 mg) and propanoic acid (100 mg) were al so significantly attractive, but significantly less so than pentanoic acid (propanoic acid was also significantly less attractive than hexan oic acid). Other fatty acids tested (heptanoic, octanoic, and nonanoic acids) were not attractive. Male/female O. parva ratios were 2/17 and 0/17 on traps baited with hexanoic and pentanoic acid respectively. T hese results are different from those of a similar study in Michigan t hat found hexanoic acid more attractive than pentanoic acid and report ed nearly 5 times more males than females on traps baited with hexanoi c acid.