94 AGRICULTURAL RESEARCH AND THE FARMER : 



workers in America have found that the Aphis spends part of 

 its hfe in trees other than the apple. The Advisory Entomo- 

 logist at Wye therefore made a thorough investigation of the 

 comphcated life-history of the pest in this country, and as a 

 result it is established that the aphis spends part of its life- 

 history on the elm during the winter in its sexual stage. Winged 

 forms are produced on the elm in the early summer, and migrate 

 to the neighbouring apple trees, so that it may be of little use 

 adopting the accustomed expedient of winter sprajdng the trees 

 with caustic soap to prevent the attack. 



Insedicidal Washes. — During the past four or five years 

 numerous types of washes have been investigated at Wye. 

 The best was found to be nicotine, at the rate of i oz. to lo 

 gallons of water, plus i lb. of soap. This, however, is an expensive 

 wash, so tests have recently been made with nicotine sulphate, 

 to see whether this substance, which is less than half the price 

 of nicotine, possessed similar insecticidal properties. It was 

 found that a wash made up of i oz. nicotine sulphate and i oz. 

 of soft soap to 10 gallons of water is just as effective as the nicotine 

 wash, and the effect is more lasting. The nicotine sulphate 

 wash was found to be particularly helpful in getting rid of the 

 Apple Case-bearer {Colleophora nigricella). This pest causes 

 severe damage to apples and plums ; it cannot be destroyed by 

 the usual method of summer spraying with arsenic, and trials 

 made during the winter of 1920-21 with various winter washes 

 proved completely ineffectual. On the other hand, the nicotine 

 sulphate spray was attended with marked success, nine-tenths 

 of the caterpillars being destroyed at one centre. 



A Simple Cure for Ground Pests. — The Advisor}^ Entomologist 

 has found during the last two years that fowls are extremely 

 valuable as a means of keeping down pests. This refers especially 

 to the Cutworms, a pernicious pest that attacks com, roots, 

 potatoes and cabbage. In Canada a method of trapping and 

 killing cutwonns with a mixture of Paris green (or lead arsenate) 

 and bran has been found successful and is widely adopted. This 

 method is certainly effective in destroying the cutworms, but in 

 this country it may also poison fowls and partridges, and its 

 use therefore is Hmited. Fowls or geese, however, will clear 

 the ground of cutworms, and since this method was advocated 

 by Wye it has been adopted by farmers in Kent. The Pear 

 Midge is another enemy against which poultry-keeping proves a 

 useful weapon. The fly in this case lays her eggs in the unopened 

 pear blossom, and the lar^•^ which hatch out are completely 

 hidden until they descend to the ground Spra^ying is therefore 



