390 



(western twelve-spotted cucumber beetle) and D. trivitatta, Mannh. 

 (western striped cucumber beetle) The process of manufacture, the 

 type of dusting machine used, and the results of the experiments are 

 described. 



For the control of Aphids other than Aphis juglandicola, Kalt., 

 a higher strength of nicotine sulphate than 2 per cent, is necessary, 

 and for Acyrthosiphon pisi, Kalt., a 10 per cent, strength should be 

 carefully applied, this Aphid being most resistant to nicotine. 



The material used against the cucumber beetles was a 10 per cent, 

 strength of nicotine sulphate (40 per cent.) in a carrier of kaolin and 

 lime. 



All experiments proved that insects are killed more effectively than 

 by liquid sprays and at less cost. All dust used was from a week to 

 several months old, except in the case of the pea aphis, for which it 

 was freshly made and kept in an air-tight container. Combination with 

 lead and sulphur kills other insects and certain noxious fungi. The 

 action of the dust is similar to that of a nicotine sulphate spray, but 

 more rapid. The only disadvantages are that its volatility causes 

 loss of strength iinless freshly manufactured and kept air-tight. It 

 can only be combined with Bordeaux mixture when the latter is dry. 

 The dust is sometimes disagreeable to the operators, especially if they 

 are inexperienced. 



Chittenden (F. H.). The Beet Leaf-beetle and its Control. — U.S. 

 Dept. Agric, Washington, D.C., Farmers' Buh. 1193, March 1921, 

 8 pp., 8 figs. 



This bulletin on Monoxia punciicollis gives, in a popular form, 

 information already noticed [R. A.E., A, ix, 203]. 



Hopkins (A. D.). The Southern Pine Beetle: A Menace to the Pine 

 Timber oJ the Southern States. — U.S. Dept. Agric, Washington, 

 D.C., Farmers' Bull. 1188, March 1921, 15 pp., 4 figs. 



Dendroctonus frontalis, Zimm. (southern pine beetle) is the most 

 destructive enemy of all pines in the Southern States, There are from 

 three to five generations annually, the first beginning with eggs 

 deposited by the beetles that attack the trees in spring and those of 

 the overwintered broods. The generations alwaj's overlap, so that 

 emergence and attacks are continuous during the period of activity. 

 The beetle is on the wing from March to December in the southern 

 section and from May to November in the northern. It attacks and 

 kills all healthy trees, infesting the middle or upper portions of the 

 trunk, in which it excavates long, winding burrows through the inner 

 layers of the living bark. The eggs are deposited in these, and the 

 larvae feed on the inner bark, mining into the outer bark to pupate. 

 The winter is passed in the bark in all stages of development. 



Investigations carried out in 1911 proved that patches of dying 

 pines were a menace to healthy trees and led to far greater destruction 

 of merchantable pines than any other factor. Evidence of the presence 

 of the beetle is shown by the foliage fading to pale green, changing 

 to yellowish and pale brown, with no trace of injury by fire. If all 

 the foliage has fallen, or partly fallen, the beetles have emerged 

 and the trees are no longer a danger to others. If the trees die between 

 March and October, the beetles will leave them after the foliage has 



