314 CALIFORNIA VEGETABLES 



such conditions, covers of paper, burlap, also serve a good purpose. 

 The whole question of cheapest and most effective frost protection 

 in California is still open, and rather than prescribe something 

 which might soon prove relatively inferior, we advise all growers 

 to read regularly some California horticultural journal in which the 

 latest discoveries and practices are described. 



INJURIOUS INSECTS AND FUNGI. 



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 invitations 

 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 

 wilts, loses color and perhaps dies without losing any appreciable 

 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, either used as a powder mixed with twenty times 

 its bulk of flour and dusted on the plant, or applied as a spray or 

 sprinkle, using one ounce of Paris green to ten or twelve gallons of 

 water. This will kill all forms of insects, large or small, which 

 make holes in leaves. It only becomes ineffective when insects 



