THE HABITS OF THE GLASSHOUSE TOMATO MOTH, HADENA ( FOLIA ) OLERACEA , AND ITS CONTROL.

SUMMARY. H. oleracea is not a normal pest of tomatoes grown under glass, and where it has become established as such it is still in some respects ill adapted to a greenhouse life on a tomato diet. The larvae eat the fruit because many of them are unable to survive on the foliage alone. In spite of this weakness, it has become a serious pest because the species is a prolific one and, once having entered a greenhouse, it usually becomes a prisoner there. In a normal year there are two complete generations and a partial third, and the moths are present in the houses continuously from February to October. Spraying the young plants with arsenate of lead largely controls the first brood of larvae, but not entirely, because moths of the first flight of the year are still emerging when it is not practicable to use a poisonous spray on the plants. The plants should be sprayed three times when the larvae appear early: (1) when the seedlings are in pots; (2) just after planting out; (3) about a month before fruit picking begins. The last operation is the most important and the two previous ones may be omitted if there are no signs of larvae feeding. Systematic moth trapping must be done throughout the growing season, because it will reduce the numbers of moths which pass out of the houses, and these, or their offspring blunder into the same or neighbouring greenhouses; and also because it is the most effective form of control when spraying is not practicable, and will reduce the infestation to a very great extent. Sixty jars baited with ale, treacle and 1 per cent, sodium fluoride should be used to each acre of glass. The dead moths should be removed frequently, and the jars should be rebaited every third week. Broken fruit must not be allowed to lie about in the houses as the moths feed on this and become more prolific. Many full grown larvae may be trapped in sacks placed about the houses. The sacks should be collected and dipped in boiling water every third week. Pupae should be destroyed in the winter. Special baskets should be kept for fruit picking, and those from the markets should never be allowed in the houses. The pest spreads rapidly through areas where the nurseries are congested owing to the escape of moths from the infested houses. It may be introduced into isolated localities by means of market baskets, or by plants purchased from infested nurseries. On its first appearance every method of control should be applied at once, as attempts to check it by picking off the larvae by hand in trade nurseries have almost invariably ended in failure.