REMEDIES FOR INSECTS 299 



crown it over a seed-hill with lumps of dirt on the corners to hold 

 the paper in place. As the young plants appear the covers are re- 

 adjusted to them at the time of hoeing. Sometimes the square of 

 paper is humped up toward one side and the folded edges pinned 

 together by a piece of wire long enough to hold the paper-laps 

 together and go into the ground a few inches to hold the cover in 

 place. This makes an opening at the south side which gets larger 

 as the plants rise. The earliest plantings bring ripe melons a month 

 earlier, through the protection which the covers afford. It is a 

 unique sight to see a large acreage covered in this way. It is, of 

 course, only efficient where frosts are infrequent and light. 



The whole question of cheapest and most effective frost pro- 

 tection in California is still open, and careful experimentation is 

 proceeding. All growers should read regularly some California 

 horticultural journal in which the latest discoveries and practices 

 are described. 



INJURIOUS INSECTS. 



It should be borne in mind that the attacks of these evils are 

 in many cases conditioned upon weakness and unthrift to the plant, 

 and the danger from both insects and blights is reduced by keeping 

 the plants in most active and vigorous growth. Lack of cultivation, 

 lack of plant food in the soil, and lack of moisture, are all invita- 

 tions to these invaders. The natural resistance of the plant is 

 broken down, and it becomes a prey to its enemies. But the best 

 growing conditions do not render plants immune against all pests. 

 Some are so aggressive that the grower has to fight to save his crop, 

 and to fight hard sometimes. 



Fortunately, warfare against insects has been greatly simpli- 

 fied during recent years by the use of remedies of comparatively 

 recent application. There are two chief divisions of insects : first, 

 biting insects, which are recognized by the gardener by the fact that 

 they make holes in the foliage ; second, sucking insects, which make 

 no holes, but pierce and extract the sap in such a way that the leaf 

 curls or wilts, loses color and perhaps dies without losing any ap- 

 preciable part of its surface. Each of these classes has its own 

 remedy. 



Remedies for Biting Insects. Insects which consume the leaf 

 surface are destroyed by poison, and this can be used in such minute 

 quantities as not to destroy the foliage nor render it dangerous for 

 food purposes unless the plant is nearly in condition for eating, and 

 then, of course, poison on the foliage is very dangerous if the foliage 

 is the edible part. If the edible part is the root or tuber, poison on 

 the foliage is not dangerous. The most widely used poison was 

 Paris green until the arsenate of lead rose to such prominence in 

 plant protection, because of its less cost and less danger of injury to 

 foliage. Paris green can be used either as a powder mixed with 

 twenty times its bulk of flour and dusted on the plant, or applied as 



