Reducing the Damage
The insecticides Sevin and TEPP are effective against the cicada, Sevin being preferred when residue restrictions do not prevent its use because of its much greater residual effectiveness. Use Sevin to protect ornamental plants, shade trees, and some fruit trees (apples, pears, peaches, plums, prunes, and cherries), and grapes, for which a tolerance has been approved. Otherwise, use TEPP.
CAUTION.—Sevin and TEPP are poisonous. Read and follow all precautions on the label. TEPP is extremely dangerous to handle. Serious illness, or even death, may result if it is swallowed, inhaled, or absorbed through the skin.
Sevin has long residual value against the cicada. One application applied when egg-laying begins will afford protection for 1 to 3 weeks, depending on the degree of infestation. Repeat applications only after reinfestation is evident. To prepare a Sevin spray, mix 2 pounds of a 50-percent wettable powder with 100 gallons of water.
TEPP acts only on direct contact with the insect. It does not affect insects that come to the tree after the spray has dried, thus orchards close to woodlands have to be sprayed almost daily. Orchards further from heavy infestations can be protected reasonably well by three or four applications a week apart. TEPP is most effective if applied early in the day, before the cicadas become active. Prepare a TEPP spray by mixing one-half pint of a 20-percent concentrate, or one-fourth pint of a 40-percent concentrate, with 100 gallons of water.
Orchard trees 1 or 2 years old may be protected by covering them with open-weave cloth, such as heavy cheese-cloth, netting, tobacco shade cloth, or the cloth used to cover tobacco seed-beds in the South. The cloth should be put in place as the cicadas begin to appear and should remain until, about 5 weeks later, most of them are gone.
Many growers refrain from planting orchards in a cicada year, or in the preceding year. Before postponing the planting of trees, they should consider cloth protection. The cost may be less than the loss represented by 1 or 2 years of delay in the development of a new orchard.
If little or no pruning is done to large trees the winter preceding an infestation, much of the injured wood can be pruned away the following winter.
In residential areas where the cicadas have previously been abundant, it is advisable not to plant young shrubs or trees around the home the year another emergence is expected.
Natural Enemies