60 PICTOBIAL PBACTICAL VEGETABLE GROWIXG. 



growth from first to last, and to secure this end the soil should be 

 well drained and deeidy tilled. Mulchings wirh soil and manure, 

 and soakirjgs of liquid manure in dry weather, are helpful in light 

 soil As an application to the plants, sulphide of putassiurn (liver of 

 sulphur) at the rate of ^ oz. per gallon of water, maybe tried. 



Thrips. — This lively little insect causes great damage to late Peas 

 in hot, dry seas^jus, It attacks the leaves and the pods, and the 

 latter curl up iitst^ad ^'A rilling. I do not believe in any mere wash 

 for this enemy, any more than I do for mildew. Cultural steps are 

 the best, such as deep tillage, feeding and mulching, combined with 

 the choice of a sort that is kn^jwu to be a vigorous grower and not 

 simply a big podder. Large p'jds are n-jt cu' much account if they 

 do not fill. The plants must be kept grc'wing. If they come to a 

 standstill the thrips can be kept in check only at an expense that the 

 value of the crop fails to justify. 



Weevil- — Pea growers often comphkn of small grubs in their pods, 

 especially in a dry season. The pods are pierced by a weevil when 

 quite young, and the grubs that hatch from the eggs laid attack the 

 Peas. The be.-t way to ensure comparative nnmunity is to produce 

 vigorous, free-grov-ing plants by good culture, supplemented by 

 occasional dustings witn soot and lime, 



Potatoes. — It would lift a ■ on the minds of vegetable 



growers if some good genius con.... _.ve us the fine qualities of the 

 best sorts in conjunction with such vig^our of constitution as sets 

 disease at defiance. It is a consummation which we shall continue 

 to wish for devoutly, but shall probably never see. A few dry 

 seasons may encourage the grower to believe that his arch-enemy. 



EEFEREXCES TO POTATO DISEASE EICxEEE OX 

 PAGE 61. 



A, infested kaf : cu le .iets :.r::\.j--:cd by the paiasiuc fungus, Phytophthora 



infestans, causing the di-:--i,se in tiie early stages, the earliest 

 indications of at: .ck tcini- rVv ^ - - ^ nee cf small bro^n:sh blct'jhes 

 on the leaves. lh>;e graha in -ize. anl are iclL'^-d 



"by a curling of t:.e leaves. In La.v:- ai a severe attack the leaves and 

 stems become blackenei and decays 1 ia the course of a few days, 

 and emit a disagreeable smell ; h. biov, n spots on the under side of the 

 leaves. These on the circumference bear, as seen by a pocket lens, 

 numbers of delicate white threads — the fuEgal outsrowths ; cle--.n 

 leaflet. 



B, the fungus wliich causes the disease in fruit : conidiophores ; 



conidia ; /, stomata of Potato leaf. 



C, a fallen conidium showing contents breaking up into zoospores. 



D, the discharge of zoospores : conidium with four zoospores not yet dis- 



charged ; A, zoospores with cilia, or hahs, by which they move more 

 readily in a drop of water, and Anally come to rest ; i, zoospore be- 

 come passive and geiminated; y, germinating or geiTU tube, which 

 enters the Potato le if. stem, or tuber, and gives rise to the disease, 



E, a conidium not broken up into zoospores, but pushing a geim tube : 



ky conidium ; germ tube. 



