300 ANNUAL, REPORT, OP THE Oflf. Doc. 



leaves the ground to climb the trees and lay eggs in the early spring. 

 Thus trees should be banded both in the fall and spring in regions 

 where canker-worms or measuring worms have been recently known, 

 in order to prevent the pests from occurring next year. 



Another mechanical contrivance that is worthy of mention, is a 

 cloth basket for protecting cucumber plants. Make this by sticking 

 the ends of two pliable twigs in the ground in such a way that the 

 cross is at the middle of the arch like the central wickets in a 

 croquet field. Over this double arch put a piece of closely woven 

 mosquito netting or cheese-cloth, and spread earth around the edges 

 to hold it down. The plant will need this protection only while 

 young enough to keep within its limits. It is, perhaps, the best 

 method to keep the plants protected from the striped cucumber 

 bug. If the meshes of the mosquito netting be large enough to 

 permit the entrance of the pest, it may sometimes crowd through, 

 but we have known this to be prevented by dusting the plants with 

 air-slaked lime to which a very little turpentine has been added. 



One of the best means of preventing the attacks of the cabbage 

 root maggot is to slit a number of pieces of paper from one side 

 to the center, and put a pad or disk of paper around each plant 

 just after it is set in the ground. When this pad is properly 

 placed around the plant, flies can not and will not lay their eggs at 

 the roots. 



///. Chemical Preventives. The use of turpentine and lime and 

 other substances might be called chemical rather than mechanical; 

 but other methods are sometimes advisable, such as using a wash 

 of potash, soap, acids, etc., in order to kill eggs or pupae and pre- 

 vent the next brood of insects, or prevent the laying of the eggs. It 

 is especially desirable that in the fall or spring fruit trees should 

 be washed with some such material. A wash of the bark of the 

 trees with potash in water gives a very satisfactory result in pre- 

 venting both diseases and insects during the coming year. White- 

 wash applied to the trunks of the trees, as well as to fences, de- 

 stroys insects and specially prevents their attacks upon trees. A 

 great deal of the value of the lime-sulphur-salt wash for the San 

 Jos6 Scale lies not in its killing the adult scale, but in preventing 

 the young insects from finding a fixing place. Lime or dilute Bor- 

 deaux mixture is used as a spray upon the leaves of potatoes for 

 flea beetles, not because it is a remedy or kills them, but because it 

 is a preventive or keeps them away. Lime is dusted around the 

 roots of cabbage, onions and radishes, and prevents the flies which 

 produce root maggots from laying their eggs in such places. Sand, 

 with a little kerosene added, is a similar preventive of such pests. 

 Not only for insects, but also for plant diseases are such chemical 

 preventives to be advocated. For example, a mi?;ture of two parts of 



