RESPONSE OF THE HOP APHID, PHORODON HUMULI (HOMOPTERA, APHIDIDAE), TOTHE APPLICATION OF JUVENILE-HORMONE ANALOG IN-FIELD TRIALS

Efficacy of the carbamate-moiety based juvenile hormone analogue W-328 against the hop aphid, Phorodon humuli (Schrank), was studied. As an effective development and reproduction regulator of aphids in laborato ry experiments, it affected hop aphid populations when sprayed as 0.1 and 0.01% water emulsion on hop seedlings in a small-scale field trial . Populations declined within the first 10 days and were almost wholly suppressed after a month. The efficacy of 0.1% emulsion of W-328 spra yed on individual hop plants in an orchard was similar, but in a field trial in a commercial orchard, with high-trellis hops, after a 0.05% emulsion spray, only aphids on the middle and bottom parts of plants w ere suppressed, while aphids on the upper newly grown untreated shoots were unaffected. The potential of using juvenile hormone analogue W-3 28 against the hop aphid in an integrated pest management strategy is discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.