Control of the grape mealybug, Pseudococcus maritimus (Hom.: Pseudococcidae), on Concord grape in Washington

Ten insecticides were evaluated for control of the mealybug, <i>Pseudococcus maritimus</i> (Ehrhorn), (Homoptera: Pseudococcidae) on Concord grape in south-central Washington during 1981 and 1982. Efficacy was determined from the number of mealybugs in samples taken throughout the season and from preharvest evaluation of mealybug damage (honeydew and sooty mold, <i>Clasdosporium</i> sp.) to fruit clusters. Results showed that parathion, malathion, and permethrin (Ambush®) effectively reduced mealybug numbers and resulted in reduced damage to clusters

Control of the grape mealybug, Pseudococcus maritimus (Hom.: Pseudococcidae), on Concord grape in Washington

Ten insecticides were evaluated for control of the mealybug, Pseudococcus maritimus (Ehrhorn), (Homoptera: Pseudococcidae) on Concord grape in south-central Washington during 1981 and 1982. Efficacy was determined from the number of mealybugs in samples taken throughout the season and from preharvest evaluation of mealybug damage (honeydew and sooty mold, Clasdosporium sp.) to fruit clusters. Results showed that parathion, malathion, and permethrin (Ambush®) effectively reduced mealybug numbers and resulted in reduced damage to clusters

Sources of Spring and Fall Hop Aphid, Phorodon humuli (Schrank), (Homoptera: Aphididae) Migrants in South Central Washington

The hop aphid, Phorodon humuli (Schrank), flies from hop, Humulus lupulus L., to its overwintering Prunus spp. hosts in the fall. The sources of these aphids were not known because much of the aphid flight occurs after hop plants are removed from fields during harvest. We found that the bottoms of hop plants remaining alive in harvested hop yards averaged 1.7 to 5.8 hop aphids per leaf in three years of sampling. Unharvested hop plants remaining after harvest averaged 32.8 to 127.1 aphids per leaf in two years. Feral hops were also infested with hop aphids in late summer and early fall. Sources for the spring aphid flight from Prunus spp. to hop included Prunus cerasifera Ehrhart, which averaged 44.0 to 105.1 aphids per shoot in two years of sampling. Fruit-type Prunus spp. trees growing on residential properties averaged 0.9 and 11.3 aphids per shoot in the same years but few of these trees were found. Plum and prune orchards averaged 0 to 5.5 aphids per shoot in two years and estimates indicate that orchard trees are much more numerous than other hop aphid host trees. Potential alternative management strategies for hop aphid control are discussed