BUREAU OF ENTOMOLOGY. 387 



The increasing importance of the European red spider, Para- 

 tetranychus pilosus, has rendered necessary a careful study of this 

 pest. The biology of the mite is being carefully investigated and 

 experiments made in orchards with various sprays for its control. 

 Indications are that a weak lubricating-oil emulsion will prove satis- 

 factory in killing both the eggs and the mites, with little or no 

 injury to the trees or foliage. The lubricating-oil emulsion has also 

 loeen tested against the San Jose scale and the wintering eggs of the 

 red spider and has proved very effective. A study of a treehopper 

 •causing considerable injury to apple by depositing eggs in the twigs 

 has been started. 



At the Wallingford, Conn., laboratory the investigations under 

 way for some years in cooperation with the Connecticut Agricul- 

 tural Experiment Station on the apple maggot were concluded dur- 

 ing the fall of 1922, and a report has been prepared giving the results 

 of the studies. It was determined that satisfactory control of the 

 apple maggot can be secured if the fruit and foliage are coated with 

 arsenate of lead during July and August, the period during which 

 the greater number of the eggs are laid. Since this treatment is to 

 kill the adult flies, which travel rather freely from tree to tree, it is 

 important not only that all parts of a given orchard should be 

 treated but also that the orchards in the neighborhood should be 

 properly sprayed. The apple thorn skeletonizer, which has become 

 a serious defoliator of apple in portions of eastern New York and in 

 <I!onnecticut, has been investigated, and a joint bulletin on the insect 

 lias been published from the Connecticut Agricultural Experiment 

 Station. Certain other miscellaneous insects have received atten- 

 tion, as the red-banded leaf-roller, false apple red-bug, apple tent 

 •caterpillar, etc. 



Beginning in the spring of 1923, a deciduous-fruit insect laboratory 

 was established in southern Indiana in cooperation with the Purdue 

 University Agricultural Experiment Station, with headquarters at 

 Yincennes. At this station will be studied the various fruit insects 

 <of importance in this rapidly developing fruit region, such as the 

 San Jose scale, the codling moth, the peach borer, a thrips injuring 

 peaches, etc. 



Insecticide investigations. — Investigations of miscellaneous in- 

 secticides have been continued at the laboratories in Washington 

 and the near-by field station at Sligo, Md. Studies under way on the 

 chemical, physical, and insecticidal properties of arsenicals, con- 

 ducted in cooperation with the Bureau of Chemistry, have been 

 -concluded and a report on the work published. In cooperation 

 with the Bureau of Plant Industry, a report has been prepared on 

 various plants tested as to insecticidal constituents. The experi- 

 ments on the effects on honeybees of spraying fruit trees during 

 "blossom and as the petals fall have been completed and a manu- 

 script submitted for publication. It is shown that spraying orchards 

 as recommended by entomologists does not result in poisoning bees 

 to any extent. A thoroughgoing study of materials attractive to 

 and repellent to insects has been undertaken, but this work has not 

 proceeded far enough to warrant specific statements as to results. 



In the tests of contact insecticides a considerable amount of data 

 has been gathered on various insecticides of this type. In cooper- 

 ation with the Bureau of Chemistry, material progress has been 



