380 FRUIT INSECTS 



In feeding they rasp or chafe away the epidermis of the ten- 

 derest parts of the flower, and then suck up the sap. The 

 delicate pistils suffer most severely from their attacks; they 

 turn black, wilt, and the development of the ovary is prevented. 

 In severe cases the whole blossom wilts and dries up within a 

 few days after opening; when only part of the ovaries are 

 destroyed, the fruit may mature, but undersized, misshapen 

 and distorted berries only are produced. 



The female inserts her minute, whitish, oblong, curved eggs 

 singly in the lower part of the calyx and in the flower stalk. 

 They hatch in about three days. The nymphs pass through 

 three immature stages and acquire wings at the third molt. 

 Only about twelve days are required for the complete Ufe- 

 cycle from egg to adult. There are several generations each year. 



Control. 



Injury by thrips is usually most severe in seasons of drought, 

 as driving rains destroy great numbers of the insects in all 

 stages of development, except the eggs. Experiments in 

 Florida hav(^ shown that this pest can b(^ r(Mi(lily destroyed by 

 thorough spraying with tobacco extract, at intervals as the 

 abundance of the insects require. ''Black Leaf 40" tobacco 

 extract should \)v dilutiHl at the rate of 1 part in lOOO ])arts 

 of water for this purpose. To make the Uquid spread and stick 

 better, 2 pounds of soap should be added to each 50 gallons. 



Keferences 



Fla. Asr. Kxp. Sta. Bull. 42, pp. 552-504. 1897. 

 Fla. Agr. Exp. Sta. Bull. 46, pp. 80-103. 1898. 



Ground-beetles 

 Harpalus caliginosus Fabricius and H. pennsylvanicus Dejean 



These two common species of the famihar black ground- 

 beetles (Fig. 332) have been reported as injuring the fruit of 



