. Circular. Insect pests; Insect pests. 6 HOW TO CONTROL THE PEAR THRIPS. middle of April the number on the trees diminishes rapidly, and by the last of April all the larvae are off the trees and in the ground. Here they work down into the first 3 or 4 inches of hard soil below the loose surface mulch and construct a tiny cell, where they remain until the following spring. Pupse.—The larvae mostly remain as such in these cells till Sep- tember, when pupation begins, pupae (fig. 5) being most abundant during October and November. Many adults can be found in the ground in December, and by the 1s
. Circular. Insect pests; Insect pests. 6 HOW TO CONTROL THE PEAR THRIPS. middle of April the number on the trees diminishes rapidly, and by the last of April all the larvae are off the trees and in the ground. Here they work down into the first 3 or 4 inches of hard soil below the loose surface mulch and construct a tiny cell, where they remain until the following spring. Pupse.—The larvae mostly remain as such in these cells till Sep- tember, when pupation begins, pupae (fig. 5) being most abundant during October and November. Many adults can be found in the ground in December, and by the 1st of January practically all the thrips are in the adult stage and apparently ready to emerge and go into the trees whenever conditions are right. Broadly speaking, the thrips spend two months of the year in the adult, egg, and larval condition on the trees and the other ten months of the year as larvae, pupae, and adults in the ground. CONTROL MEASURES. The pear thrips is in some respects an unusual insect in that it remains in a dormant or semidormant condi- tion for about ten months of the year. Although on the trees for only two months out of the twelve, it is able in this short time, in the absence of treatment, to completely destroy all prospects of a crop of fruit, in many cases within a very few days. The trees are attacked at the period of bud swelling and blossoming, when they are most susceptible to injury. These minute insects come literally in swarms, and may, if left alone, completely destroy all of the fruit buds of an orchard in four or five days. Many cases have been known where a delay of four or five days in spraying resulted in loss of the entire crop of fruit, and in some cases half of all the buds were killed in three days after the thrips appeared on the trees in great numbers. In view of this condition it is very evident that any means of control must be very thorough and done in the most exacting manner at the proper time. EXPERIMENTS IN THRIPS CONTRO
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