239 



found that where the perceEtage of infestation is sufficiently high, 

 dusting has reduced it considerably ; while incases of low infestation, 

 such as 2 or 3 per cent., it is doubtful whether the treatment pays 

 for itself. 



Shear (W. V.). The Eelworm and Potatoes. —M/%. Bull Cat. Slate 

 Dej)'. Agric, Sacramento, ix, no. 3, March 1920, pp. 69-71, 1 fig. 



Potatoes in California are heavily infested with eelworms, which 

 attack the outer layer of the potatoes to a depth of about \ in. One 

 tuber may contain many thousands of these Nematodes, which will 

 cause it to shrivel prematurely and decay. Infestation is largely 

 spread by the sowing of infested tubers, especially when table potatoes 

 are used for seed purposes, and also by throwing the parings from 

 infested potatoes on to the land either as rubbish or to serve as 

 manure. It is highly important that the distribution of infested 

 potatoes should be rigidly prevented, and this can be done by 

 planting only disease-free seed on disease- free land. 



NouGAEET (R. L.). Sulphur Fumigation for the Control of Mealybug 

 {Pseudococcus hakeii, Essig) on Grape Vines in the Vineyard. — 

 Mthhj. Bull. Cat. State Dept. Agric., Sacramento, ix, nos. 1-2 & 3, 

 January, February and March 1920, pp. 26-31 & 83-85, 2 figs. 



Fumigation by means of sulphur burned under a tent has been 

 found very effective against the mealy-bug, Pseudococcus hakeri, Essig, 

 on grape-vines. The life-history of the insect is different on grapes from 

 that on any other food-plant. On grape there are two distinct genera- 

 tions, which do not overlap, as is the case on citrus or pear ; the first 

 hatches in June and is the progeny of the overwintering larvae, the 

 second hatches during September and October. Hibernation occurs 

 in the larval stage, within the ovisac. Fumigation, therefore, is 

 directed against the larvae only, as there are no eggs to be taken into 

 consideration. Full instructions for the process of fumigation are 

 given, advice as to materials, and the cost of fumigation per vine has 

 been worked out. 



The mealy-bug, being wingless and very slow in locomotion, seldom 

 spreads by its own efforts to neighbouring vines, unless these overlap 

 or touch, but is largely disseminated by wind, on the clothes of 

 grape-pickers and in the grape-picking boxes. These boxes should 

 always be fumigated after use by burning ^ lb. sulphur per 100 cu. ft. 

 of space in a fruit-fumigating shed or under canvas, the process 

 lasting at least half an hour. Honeydew on grapes is a positive sign 

 of the presence of the mealy-bug, and all bunches of grapes marked 

 with it should be refused at the packing shed. 



WooDwoRTH (H. E.). Damage to Nursery Plants by the Fh-e Ant 

 {Solcnopsis geminata, subsp. maniosa, Wheeler). — MlhJy. Bull. Cal. 

 Slate Depl. Agric, Sacrainen'o, ix, no. 3, March 1920, pp. 87-88, 

 Ifig. 



The ant, Solenopsis geminata subsp. maniosa, Wheeler, commonly 

 known as the fire ant, has been very mjurious in Cahfornia to passion 

 vines (Passiflora edulis). The ants build their nests in a mound from 



