PECAN PHYLLOXERA
The pecan phylloxera, Phylloxera devastatris Perg., and the pecan leaf phylloxera, P. notabilis Perg., produce galls on the new growth of pecans. Leaves, twigs and nuts may be affected.
The galls are conspicuous swellings, [Figure 17], which attain a size of from one-tenth to 1 inch in diameter. They are caused by a soft-bodied insect which is closely related to aphids.
The winter is passed in the egg stage in crevices in the bark. In the spring, the egg hatches and the tiny nymph feeds on the tender, young growth, apparently secreting a substance which stimulates the plant tissues to develop into galls.
After the nymph reaches maturity, a number of eggs are deposited inside the gall. The young nymphs of the succeeding generation develop within the gall, which splits open in 1 to 3 weeks, liberating them. Several generations follow during the summer and fall, as long as there is fresh young growth on the tree. From 4 to 5 weeks are required for each generation[4].
Control.—The dormant oil spray recommended for obscure scale control will prevent the development of phylloxera. If dormant oil is not applied, use 2 pints of nicotine sulfate plus 6 pounds of soap; 3 pounds of 25 percent malathion wettable powder; or two and a half pounds of 10 percent gamma isomer BHC wettable powder per 100 gallons of water when the leaves are one-third grown.