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.
SAWFLIES
Sawfly larvae, Periclista sp. and others, feed on the foliage of pecans during April and early May. The larvae, which are light green, chew holes in the leaves. Usually the midrib and veins are left intact, giving the leaflets a lacy appearance, [Figure 18].
The adults closely resemble wasps, except that they are not “wasp-waisted.”
Fig. 17. Developing galls of the pecan phylloxera. Note the open gall on the lower leaf.
Control.—The larvae may be controlled with an application of 2 pounds of 50 percent DDT wettable powder or 1 pound of 25 percent parathion wettable powder per 100 gallons of water.
