218 THE MONTHLY BULLETIN. 



The Bean Thrips and the Onion Thrips. 



The bean thrips and the onion thrips are two minute active insects 

 belonging to the same order. The adult bean thrips are blackish in 

 color with white and black banded wings, and are about one twenty- 

 fourth of an inch in length. The bean thrips is a general feeder damag- 

 ing beans, alfalfa, cotton, beets, lettuce, potatoes, tomatoes and pears, 

 besides other plants. Infested leaves turn yellowish or whitish, then 

 fall. This may be continued until the entire plant is defoliated. The 

 onion thrips is especially destructive to the onions and unlike the bean 

 thrips the adult is pale yellow in color. The Government formula used 

 against the pear thrips can be used against this species, the formula 

 being black-leaf 40, 1 to 2,000, and 3 per cent distillate oil emulsion. 

 On plants having very tender foliage a flour paste spray consisting of 

 6 to 8 gallons of flour paste to 100 gallons of water, thoroughly coating 

 the infested plants, will be eifective. 



PARASITIC INSECTS. 



Braconid Parasites. 



These hymenopterous parasites are well afield at this time. One 

 species (Aphidius testacelpes) preys upon the melon or citrus aphis 

 {Aphis gossypii), the apple aphis {A. pomi), the orange aphid {Tox- 

 optera aurantice) , the peach aphid {Myzus persicce), etc. 



I have before me specimens of the mummified aphids of the orange 

 aphis, in which case the plant lice were almost exterminated. The 

 parasitized lice change color and form, becoming a dirty white and 

 nearly spherical. 



It is possible that these Braconid flies may become second in impor- 

 tance only to the Hippodamia as foes to these destructive sappers of our 

 trees and other plants. We may well increase our efl^orts to introduce 

 them to all sections of aphid attack. — A. J. Cook. 



PLANT DISEASES. 



Pear Blight. 



This seems to be a pear blight year. Pear orchardists are having a 

 busy season cutting out the blight which was spread, probably by in- 

 sects, from the overwintering "blight left unnoticed in the orchard or 

 adjoining orchards. We have received numerous specimens of infested 

 twigs which are evidently blossom infection. It is commonly known 

 that this disease is of a bacterial nature and that the infested blossoms, 

 twigs and leaves blacken and die. The method of control is to cut out 

 infested portions below any sign of infection and to sterilize both 

 wounds and pruning tools with corrosive sublimate, 1 to 1,000. 



Apple and Pear Scab. 



The apple and pear scab fungus causes scabby patches on the fruit. 

 If infestation is serious Bordeaux mixture 5/6/50 formula may be used 

 to advantage several times during the season. 



Grape Mildew. 



The fungous disease known as grape mildew is observed as a white 

 powdery growth on the leaves and fruit clusters of the grape. The 

 method of controlling this disease is to thoroughly dust the vineyard 

 with flowers of sulphur. 



