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the eggs laid by the latter give rise to a similar cycle in 

 the following spring. Some Aphides are restricted to a 

 particular species of plant, while others have alternate 

 hosts. Thus the Hop Aphis winters on damson and flies 

 to hops in the spring. The Elm Aphis goes to the roots 

 of Ribes> the Mealy Plum Aphis to rushes and aquatic 

 grasses, and the Bean Aphis to mangolds, poppies, dock, 

 etc. Some of the most destructive Aphides are the Bean 

 Aphis (Aphis mmicis), Currant Aphides (Rkopalo siphon 

 ribis Linn, and Myzus ribis Linn.), Hop and Damson 

 Aphis (TPhofodon huniuli), Apple Aphides (A -phis pomi 

 De Geer., Aphis sorbi Kalt, and Aphis jitchii Sand.), 

 Plum Aphis (Aphis pruni Reaum.), Cabbage Aphis (Aphis 

 bras sic ae Linn,), Turnip Aphis (Aphis rapae Curt.), Rose 

 Aphides (species of St phono phora\ Woolly Aphis (Schi- 

 zoneura lanigerd), and others. In dealing with these pests 

 it is important to remember that when using insecticides 

 contact insecticides only are of use. Insecticides fre- 

 quently do not destroy the eggs and, notwithstanding 

 spraying, fresh broods appear from the unaffected eggs. 

 When the leaves of the host plant are curled insecticides 

 are of little value, as they do not reach the Aphides 

 within, Frequently the undersides of leaves alone shelter 

 the Aphides, and spraying must be adjusted so as to 

 reach them. The earlier measures are applied after the 

 appearance of Aphides, the better the chances are of 

 success, before the latter become numerous. 



The Bean Aphis (17) is usually black and very con- 

 spicuous; it especially attacks broad beans. It appears 

 when the beans commence to bloom and attacks the heads. 

 It breeds rapidly, covering the plants with a black sticky 

 mass which gradually extends downwards over the stems 

 and leaves. A simple and effective measure is to pick 

 .off the infested tops as soon as any Aphides are seen 

 thereon, and drop them straight away into- a pail of lime. 

 In bad infestations spring spraying with a knapsack 

 sprayer is necessary. Two applications are desirable and 

 are usually successful. The Cabbage Aphis (17) may also 

 infest swedes and turnips. It usually appears about 

 May, but evidences of injury are not generally noticeable 

 until June, when the leaves begin to show blister-like 

 areas on the upper surface, while the Aphides are to be 

 found in the corresponding hollows on the undersides of 

 the leaves. The leaves become yellow and discoloured, 



