253 



ground, travelling more rapidly at high temperatures than low. Such 

 preventive measures as checking the mites on their winter host-plants, 

 reducing wind dispersion, and natural control by chmatic conditions 

 and predatory animals are insufficient. The use of sulphur is therefore 

 recommended, either in powder or dissolved form. The methods of 

 applying these two forms are discussed and compared. A powder 

 sprayer is advised as being more economical and effectual than hand 

 machines. The sulphur treatment should be given during the first 

 week in July, irrespective of weather or presence of the mites. The 

 same treatment should be given for Bryohia prafensis, found in the 

 coast districts of California, but only at temperatures from 70 to 

 100° F. when sulphur will volatilise readily. The winter is passed 

 by this mite in the egg-stage on the tree that serves as a food-plant. 

 Winter treatment of the eggs has given variable results, a 12| to 15 

 per cent, oil emulsion being as satisfactory as any. 



Maskew (F.). Quarantine Div/sjon. Report for the Month of November, 



1917. — Mthly. Bull. Cal. State Commiss. Hortic., Sacramento, vi, 

 no. 3, March 1918, pp. 168-169. 



The following pests were intercepted : — From Samoa : Eulecanium 

 sp. on Hibiscus. From Central America : Aspidiotus cyanophyUi and 

 Selenaspidus articuhtus on bananas. From China : Weevil larvae in 

 sweet potatoes. From Hawaii : Diaspis bromeliae on pineapples ; 

 Pseudococcus bromeliae on pineapples and bananas ; weevil larvae in 

 sweet potatoes and seed pods ; Chrysomphalus aonidum and Pseudo- 

 coccus sp. on green coconuts ; Coccus longulus on betel leaves. From 

 Holland ; Eumerus strigatus in bulbs. From Isle of Pines : Lepido- 

 saphes beckii, Parlatoria pergandii, and Chrysomphalus aonidum on 

 grapefruit. From Japan : Lepidopterous larvae in dried persimmons ; 

 Poliaspis pini on pot plants. From Idaho : Tetranychids on apples. 

 From Mexico : Lepidopterous larvae in dates. From Nevada : 

 Rhizoctonia and eel worm in potatoes. From Ohio : Weevils in 

 chestnuts and Coccus hesperidum on crotons. From Oregon : Rhizoc- 

 tonia on potatoes ; Venturia inaequalis on apples. From Temiessee : 

 Unidentified larvae in chestnuts. From Louisiana : Saissetia oleae 

 ■on bananas. From Washington : Venturia pyrina on pears ; eggs 

 of Tetranychids, Cydia pomonella and Leptothyrium po7ni on apples ; 

 Rhizoctonia and Heterodera radicicola on potatoes. 



Moore (W.) & Graham (S. A.). Toxicity of Volatile Organic 

 Compounds to Insect Eggs.— Ji. Agric. Research, Washington, D.C., 

 xii, no. 9, 4th March 1918, pp. 579-587. 



The studies recorded in this paper were undertaken in view of the 

 work of the senior author showing that the toxicity of organic com- 

 pounds to insects is related to their volatility, of which the boiling 

 point is a general index [see this Review, Ser. B, v, pp. 131 and 174.]. 

 The eggs chosen for the experiments were those of the jDotato beetle, 

 Leptinotarsa decemliyieata. Say, of which 100 per cent, of untreated 

 •eggs hatched. Various chemicals were used, their effects being 

 studied by dipping the egg-clusters in the chemical to be tested, by 

 spraying the clusters with an atomizer and by exposing the eggs to 



