Departmeistal Activities. 19 



Cotton Stainers and Cotton Staining. — Cotton stainers usually 

 get the whole blame for any staining- or discolouring- of the cotton 

 lint. It is undoubtedly true that stainers and other sucking' bug-s 

 of a like nature do cause some staininr?-, and this staining- may be the 

 direct result of the insects sucking- the juices from the cotton seed oi 

 piercing- the rind of the boll. On the other hand, the staining n- 

 be brought about indirectly by the subsequent invasion of the boll 

 by bacteria and fungi through the bug punctures. Any extensive, 

 staining of the lint by the excrement from the stainers is largely 

 discredited now; and staining by the crushing of the bodies of tht 

 insects is relatively infreciuent, and not of much importance. 



Observations made in the Kustenburg District, where f 

 weather at picking time is usually dry and sunny, show that stainers 

 may be present in great numbers, and the percentage of stained lint 

 very low. Again, in the eastern Transvaal, where weather condi- 

 tions may be moister at picking time, considerable staining has been 

 observed in fields having only a moderate number of stainers. 



The control of stainers by any direct method is not practicable. 

 However, a thorough clean-up after the cotton crop is off will do 

 much to reduce the numbers of these pests. Surroundings clean of 

 plants related to cotton should be maintained. The stainers usually 

 remain on their native food-plants till late in the summer, when they 

 migrate to the cotton plants; on this nourishing supply of food 

 they increase rapidly. But then it is too late to do much to check 

 them. Collecting the stainers into tins, which may be easily done, 

 as they congregate on the opening bolls, is a method employed in 

 some countries; but it is doubtful if the method will prove practic- 

 able in this country Avhere labour costs are higher. 



Weevils and Fruit Trees, — Many reports reach the Division of 

 injury to young orchards by small, dull-coloured weevils or snout- 

 beetles. These are always wingless forms, whose earlier stages are 

 passed underground, where the grubs most probably feed on roots of 

 veld plants. The beetle stage does not last long, and for the greater 

 part of the year the creatures live a hidden existence. Since 

 the mischief usually happens to trees nnjre or less recently set out 

 in new lands which previously only carried native plants, it follows 

 that the weevils emerging from the soil are compelled to attack the 

 trees in the absence of their normal food sapply. It would be differ- 

 ent if they could fly, as they would then mig]-ate in search of what 

 is more natural to them. But, being compelled to crawl and pressed 

 by hunger, they congregate upon the young fruit trees. This trouble 

 is usually one of but a season in orchards that are kept clean, and is 

 best met by hand-picking the insects until their numbers are suffici- 

 ently reduced. An application of arsenate of lead to the young 

 trees may also give them some protection. 



The Lily Borer. — The jVatal Ejitoinologist has found that the 

 mischief of the crinum borer, BritJiys pancreatii, Cyr., can often 

 successfully be checked by spraying the infested plants with arsenate 

 of lead. This pest feeds in the interior of the leaves and stalks; 

 but, wlien the food su])ply in one part gives out, the caterpillar 

 migrates to fresh leaves or stalks and again eats its way in. It is 

 due to these compulsoiy migrations that the poison acts as an 

 effective control measure. 



