FARMERS BULLETIN 856. 



Fungi and bacteria grow and multiply rapidly when conditionsj 

 suit them. Instead of seeds they form spores, which are minute! 

 bodies produced in great numbers, to be spread by wind, water, or^ 

 other agencies, and, like seeds, these spores may germinate, grow into 

 a plant or fruit, and start a new center of disease. 



The weather has an important influence on the development of 

 fungous diseases, moisture and warmth being necessary. 



True insects are small creatures which in the adult stage have 

 rather hard bodies divided into three portions, head, thorax (chest), 

 and abdomen (belly). They have a single pair of antennae, or " feel- 

 ers," normally three pairs of legs, and usually one or two pairs of 

 wings. Among injurious forms of true insects are beetles, butter- 

 flies, moths, sawflies, ants^ 

 flies, grasshoppers, plant- 

 bugs, thrips, and plant-lice. 

 Other small creatures in a 

 general way are popularly 

 classified as insects, such as 

 sowbugs, red spiders, mites, 

 and th'ousa n d-1 egged 

 " worms," or millipedes. 



Insects are classified into 

 ( 1 ) chewing or biting forms, 

 which devour leaves and 

 other portions of plants; and (2) sucking forms, which injure and 

 destroy plants by draining their vital life juices. For the first class, 

 arsenicals are the best remedies ; for the second class, contact poisons 

 are used. 



(lardeners should learn to know the insects which are useful in 

 destroying injurious insects. Prominent among these is the con- 

 vergent ladybird (fig. 1). It destroys not only all forms of garden 

 plant-lice but the eggs of various insects, such as the Colorado potato 

 beetle. Other beneficial insects are wasps, ichneumon and chalcis 

 flies (minute, wasplike insects), ground beetles, soldier bugs, syrphus 

 flies, tachina flies, and lace-wing flies. Were it not for the natural 

 enemies of the potato beetle and of cabbage worms, army worms, 

 and similar pests, all vegetable crops probably would be failures. 



Fig. 1. — The convergent ladybird (Jlippodu 

 vonvergetift) , an enemy of garden insects 

 Adult ; b, pupa ; c, larva. Enlarged. 



PREVENTION OF DISEASES AND INSECT INFESTATION. 



The gardener who starts with a clean soil may do much to keep 

 insects and diseases out, and thus save the trouble and cost of apply- 

 ing spraj^s. Prevention is better than cure, especially in the home 

 garden, which usually must be planted on the same ground, year 

 after year, 



