Issue link: http://read.dmtmag.com/i/466321
www.goodfruit.com GOOD FRUIT GROWER MARCH 1, 2015 13 he grows them for alfalfa growers and teaches them how to grow their own. As it turns out, the nematodes that attack alfalfa snout beetle also attack plum curculio, which is a pest of apples, cherries, peaches, and plums, and they attack Japanese beetle as well. Early field trials in four New York orchard plantings have shown a reduction of up to 70 to 97 percent in the populations of plum curculio, Agnello said. Shields is also assisting Cornell ento- mologist Dr. Greg Loeb and his team, who are investigating the use of nem- atodes to control grub populations in New York grape vineyards as a way to manage Japanese beetles, which defoliate grapevines. Key insect Plum curculio is the bane of apple and stone fruit growers east of the Rocky Mountains, Agnello said, and they rou- tinely spray two or three times shortly after petal fall to control the insect. Even then, he said, growers will experience damage as high as 3 percent. Most of the damage to apples comes from oviposition stings, but some larvae persist in fruit. "Apple is not really a great host for plum curculio," he said. Adult curculio lay eggs in tiny fruit, first making a slit in the apple to insert an egg. If the fruits remain on the tree, the eggs fail to hatch, crushed by the flesh of the growing fruitlet. But the slit leaves a scar that can make the mature fruit unsalable. ® 'ǞǞĔ'6Ĕ%ǟ Ǟ%ĔǞmR6ĔSnĔǞǞǟǞ ĔǞĔ6Ĕ "ǞǞǞĔĔǞǟ ǟĔĔǞĔ Ĕ Delegate ® Insecticide. ǟ ǟǞǟ Ǟ ǟĔǞ Ǟ Ǟǟ ǎ Ĕ ǞǟǟǟǟĔǎĔ Ǟ1ǟ 6Ǟ you can Ĕ Ĕǎ ǟ Ǟ Ĕ ǟ ǎǟJ Q%ĔǟĔ Q Thrips Q Leafroller Q Leafminer QǗ&Ĕ ǟ6ĔĔǟǞ Q%ǎǟ Q Pear psylla , Ǟ Ĕ Ĕ Ĕ Ǟ Ǟǟ ǟĔ" ǞǞǟǞĔ mǟ Ĕ ǞnĔ6Ǟ Ǟ Ĕǎ Ĕ ǟ ǟĔǞ'ĔǞĔǟǟ 6Ǟ ǟ ǟ Ĕ MULTIPLE PESTS LURK. COINCIDENTALLY, DELEGATE ® CONTROLS MULTIPLE PESTS. PHOTO COURTESY OF ART AGNELLO Wax moth larvae are used to grow the nematodes. The larvae contain the entomopathogenic nematode infective juveniles, and they are dissolved in water to make a solution that can be applied to WKHRUFKDUG½RRUXVLQJDQ$79PRXQWHG sprayer. After the eggs are laid, many of the infested fruit fall during June drop. In fruits that are on the ground, feeding larvae emerge from the fruit and burrow into the soil, where they complete their life cycle. It is there that they are prey for the soil-dwelling nematodes. Organic problem While conventional growers get pretty good control with insecticides, organic growers don't have many insecticides that are approved and effective. Their main defense has been multiple applications of kaolin clay to act as a physical barrier against the insect. Organic treatment programs can easily range from $150 to $450 per acre per year, and fruit damage often remains at five to 20 per- cent, Agnello said. "Although our current work focuses on organic production, conventional apple growers who see plum curculio damage to 2 or 3 percent of their crops in spite of as many as three insecticidal treatments per year will be able to add the use of nematodes to their pest control practices," he said. The two nematodes involved are Steinernema carpocapsae and Steinernema feltiae, and together they provide a dual mode of attack. In an article in the Spring 2014 edition of New York Fruit Quarterly, the Cornell entomologists said that "Native nematode strains persisting for ϔ of a single application suppressing insect populations for multiple seasons." —Elson Shields