ENEMIES.

A tachina fly, Linnaemyia comta Fall., identified by W. R. Walton, and an ichneumon fly, Enicospilus purgatus Say, identified by A. B. Gahan, have been reared from larvæ collected at Baton Rouge. A sarcophagid fly, determined by J. M. Aldrich as Sarcophaga helicis Townsend, issued from a rearing jar containing larvæ of Feltia annexa and may have been parasitic on them. Dead larvæ, invested with fungus, have been found also in rearing cages. The fungus has been identified by Dr. A. T. Speare as Entomophthora virescens Thaxter.

METHODS OF CONTROL.

Experiments indicate that, of the four methods of control following, only the use of poisoned baits and the treatment of attacked plants with arsenicals will prove satisfactory. The latter method is especially applicable when large plants are being injured and in certain instances, especially where severe injury to foliage is being done, both methods might be used simultaneously to advantage.

HAND PICKING.

One control measure is suggested by the fact that larvæ are found during the day in soil about plants on which they have fed during the previous night. This method is sometimes followed in Louisiana. Vegetable fields, usually fields where transplanting has been recently done, are examined and when cutworm injury is noted, search for the larva is made in the soil about the base of the damaged plant. If the larva is discovered it is killed. This work can be done best in the early morning. Later in the day wilting of the severed part of the plant makes it more difficult to locate the injury, and the larva may move from the injured plant or bury itself deeper in the soil as the day advances.

This method of control, even if practiced for several days and carefully done, is expensive and by no means satisfactory. It is impossible to discover all the larvæ in a field by following such a method and the plan furthermore rests on the unsatisfactory basis that some injury must be done before the larva is killed. If larvæ are abundant, a large number of young plants are often cut off during the first night after they have been set out.

BARRIERS AROUND PLANTS.

Experiments made in cages and in the field indicate that in setting out plants injury may be reduced, to a certain degree, by wrapping the stems with newspaper or oiled paper, or placing cylinders of wrapping paper or metal about them. Such practices do not entirely

prevent injury and besides the expense of placing these barriers around the plants, their presence may retard the growth of the plants. In the experiments larvæ sometimes ascended the barriers, either when the stems were wrapped with the material or when the barrier was at some little distance from the stem. If food plants, unprotected by barriers, are present there is less damage to the protected plants than is the case when only protected plants can be reached. This is shown in Plate IV, A, B, D. The plants protected by the cans, containers such as canned goods are sold in, with the tops and bottoms removed, show no injury, while the unprotected plants have been seriously fed upon.

POISONED BAITS.

Satisfactory results have been obtained in destroying the larvæ in cages and in the field with poisoned bran mash. A mixture made up in the following proportions has given good results:

Bran
Molasses.

Paris green
Water____

Juice and finely chopped rind and pulp of 2 oranges.

-pounds_- 10

---quart__ 1

--pound 1
--quarts__ 7

In cages where young cabbage plants were growing larvæ were observed to feed upon this poisoned mash after it had been scattered thinly over the soil. No damage to the plants was noted and larvæ were dead on the following day. Of 202 larvæ collected from the soil 88 per cent were dead within three days after the mixture had been scattered over a field of Brussels sprouts that were being injured. A portion of the remainder apparently were not killed because they had completed their growth and stopped feeding before the poisoned mash was put out.

A mixture of 20 pounds of bran, 2 pounds of powdered arsenate of lead, gallon of molasses, and about 14 quarts of water has also given good results in killing larvæ in the field.

When the larvæ are found to occur in abundance in a field at plowing time and this field is to be immediately planted, it would seem advisable to apply poisoned baits before the field is planted rather than to wait until the crop shows injury.

TREATING PLANTS WITH ARSENICALS.

When the larvæ are feeding upon the leaves of plants it is possible to reduce their numbers by applying arsenicals to the foliage. This method is especially applicable in the case of plants that have reached a considerable size, and under certain conditions the arsenical may at the same time prevent injury by other leaf-eating insects. Plate V shows two boxes of cabbage plants. The plants in

one box were sprayed with powdered arsenate of lead at the rate of 2 pounds to 50 gallons of water, with 2 pounds of yellow laundry soap added. The plants in the other box were left untreated. Larvæ were then confined in both boxes. The appearance of the sprayed plants 23 days later is shown in Plate V, A, and that of the unsprayed plants in Plate V, B. The larvæ in the box containing the foliage to which poison was applied fed but little before being killed, while those in the other box continued to feed until their larval growth was completed.