RED-HEADED PINE SAWFLY

a. shows a cluster of larvae feeding on a pine twig; b, adult male. (a and b, about natural size.) c and d are the female and egg niches in a needle, respectively. e, Mature larva. f, Cocoon. (c, d, e, and f, all greatly enlarged.)

RED-HEADED PINE SAWFLY

The red-headed pine sawfly attacks young pine trees in nurseries, plantations, areas of natural reproduction, parks, and ornamental plantings. It occurs throughout the eastern half of the United States, in eastern Canada, and perhaps in Missouri and Arkansas.

The adults are robust and four-winged. Their name comes from the sawlike egg-laying apparatus that the female uses to make slits in the needles in which to deposit her eggs. The larvae mature in 25 to 31 days. The winter is passed in the pre-pupal stage in capsule-shaped cocoons in the duff or topsoil under infested trees.

This sawfly feeds on many kinds of pines and some other conifers. It prefers the hard pines. The young larvae prefer the old needles as food, but the maturing larvae will eat the new foliage and the tender bark of young twigs.

Its life history is rather complicated. There may be one, one and one-half, or two generations a year. Some adults of each generation emerge the year the eggs are laid, but the rest go over until the following year. As a result, broods of larvae may be found feeding nearly the entire season; the length of the period depends somewhat on the climate.

Control: Lead arsenate or DDT applied to the foliage will kill any larvae present. Small infestations on a few trees around residences can be destroyed by hand-picking the larvae or by dislodging them with a stream of water from a hose. They can then be crushed or otherwise destroyed.

In nurseries, plantations, or areas of natural reproduction, sprays can be applied with hydraulic equipment or mist blowers. (1) For hydraulic sprays use either 1 1/2 tablespoonfuls of the 50 percent wettable DDT powder or 3 level tablespoonfuls of arsenate of lead in a gallon of water, or 2 and 4 pounds respectively in 100 gallons. To increase the stickiness of this spray add three-fourths teaspoonful of linseed oil per gallon, or three-fourths pint (12 ounces) per 100 gallons of the spray mixture. (2) For mist blowers use a 6-percent concentrated emulsion or suspension at 2 gallons per acre. Quantities to make up 1 gallon of DDT concentrate emulsion consist of: DDT, one-half pound; xylene, 1 1/4 pint; Triton X-100, three-fourths ounce (1 1/2 tablespoonfuls); and water to make 1 gallon. Materials needed for 1 gallon of the suspension are: Arsenate of lead, three-fourths pound; cottonseed or fish oil, 4 1/2 ounces; white mineral oil, 1 1/2 ounces (3 tablespoonfuls); and water to make 1 gallon.

A careful survey of sprayed areas should be made up to 14 months following treatment because some of the larvae may have formed cocoons and may have been protected at the time of application of the chemical. Another treatment therefore may be necessary.