530 



of the plants and frequently allo\ving access to fungi and bacteria. 

 The vines should be destroyed as soon as the crop has been harvested. 

 The ground should then be harrowed Hghtly and ploughed deeply the 

 following spring, not later than 15th April, to bury the pupae. After 

 the plants become infested, it is advisable to cover the crowns with 

 soil in order to start new root- growth above the wounds caused by the 

 larvae. A two or three year rotation of crops is recommended. 

 Epilachim borealis, F. (squash ladybird beetle) is troublesome on 

 water-melons, which are very susceptible to injury from sprays. 

 Arsenate of lead powder at the rate of 2 lb. to 50 U.S. gals, water will 

 kill the beetles without injury to plants. The first application should 

 be made in June or when the beetles are first noticed on the plants, 

 and should be continued once a week in order to protect the new 

 growth, every portion of the plant being thoroughly covered with 

 the spray. The vines should be well coated with spray when 

 the eggs hatch, as the larvae will commence to feed on the stem 

 near the spot where they hatched, whether arsenicals are present 

 or not. 



Bean and pea pests include Ceratoma trifurcafa, Forst. (bean-leaf 

 beetle), which feeds on the foliage and is frequently associated with 

 Diabrotica duodecimpunctata ; both of these pests can be controlled 

 by spraying the plants with H lb. of powdered lead arsenate to 50 

 U.S. gals, water, just before the blossoms open. Aphis nmiicis, L. 

 (bean aphis) infests many species of weeds, as well as cowpeas, beans, 

 spinach, beets and clovers. When found on the stems and under-sides 

 of the leaves of beans they can be controlled by spraying with 4 lb. 

 fish-oil soap, 8| oz. 40% nicotine-sulphate, 50 tj.S. gals, water. An 

 arsenate of lead and fish-oil soap mixture must not be used on beans, 

 as inj ury to the plants would result ; the two materials may however 

 be applied separately with a week's interval between the apphcations. 

 Acyrthosiphon {Macrosiphum) pisi, Kalt. (pea aphis) infests pea crops 

 in May and again in September. As the insect passes the winter 

 largely on clover, it is not advisable to plant peas in the vicinity of 

 clover fields. As soon as the first Aphids appear on the peas control 

 measures should be applied. These have already been discussed [see 

 this Review, Ser. A, iii, p. 155]. More recent experiments have led to 

 the conclusion that more effective results can be obtained with the 

 formula : 6| oz. nicotine-sulphate 40% ; 5 lb. fish-oil soap ; water, 

 50 U.S. gals. This spray should be applied under high pressure so 

 that it will reach all parts of the plants and the treatment should be 

 repeated at least once a week during May and September. The small, 

 early varieties of peas are recommended, as the later ones are more 

 liable to injury and more difficult to spray. The plants should be 

 set in rows four feet apart so that the sprayer may be driven between 

 them. The practice of intercropping peas with cucumbers or beans 

 in the spring or with beans and strawberries in the autumn is 

 recommended. , 



Onions are attacked by Thrips tabaci, Lind. (onion thrips), which 

 niay be controlled by spra}nng with 4 lb. fish-oil soap and 8| oz. 

 nicotine-sulphate 40%, to 50 U.S. gals, water. The spray must be 

 applied thoroughly, as many of the insects hide in the axils of the 

 leaves. Three or four apphcations, at about four days' interval, are 

 usually necessary to control them. 



