PLANT DISEASES. 95 



of no use against the pest, and so far no effective soil insecticide 

 has been discovered. Fowls, however, relish the larvae, over 400 

 having been counted in one young chicken. In numerous 

 instances the pest has been controlled by this means. 



Red Spider. — Investigations have also been carried out in 

 regard to destruction of Red spider. Wheat flour at to lb. to 

 100 gallons of water has proved quite effectual for those species 

 which can be treated with sprays, such as Hop and Fruit Red 

 Spiders. 



Glasshouse Pests. 



Experimental and Research Station, Cheshunt, Herts. 



Glasshouse Tomato Moth {Hadena oleracea). — The larvae of 

 this moth cause extensive damage to glasshouse plants and fruit. 

 In a recent year the damage in the LeaVaUey alone was estimated 

 at ^30,ooo,quite apart from the heavy cost of picking off the larvae 

 by hand. In some cases the whole staff of a nursery has been 

 occupied on this work, to the neglect of other duties, in order to 

 keep the pest within bounds. The life history and habits of the 

 moth formed the subject of a thorough investigation by the 

 Entomologist attached to the Station, with a view to finding out 

 methods of control. As a result, the following method of control 

 was elaborated : — 



(i) Spraying with Arsenate of Lead. 



6 lb. Arsenate of Lead paste. 



100 gallons of water. 



2 oz. Saponin (to be added to water before the paste). 

 Spray the plants just before planting out and again a 

 month before first fruit is to be picked. 



(2) Trapping of Moths. 



This reduces the infestation when spraying is no longer 

 possible. Traps consist of 2 lb. fruit jars, each containing about 

 3 oz. of the following mixture : — thick brown treacle, one part ; 

 ale, two parts; sodium fluoride, one per cent. Six jars are used 

 to each 200 ft. house. 



(3) Destruction of Chrysalids. 



{a) Baskets and canes dipped in boiling water. 

 {h) Houses drenched with boiling water. 



As the result of the adoption of this treatment in the Lea 

 VaUey the loss from caterpillar is now practically nil. 



