395 



To obviate these dangers it is suggested that the baits should not 

 be used generally outside the area of infestation in any plantation. 

 They should not be placed among apparently uninfested stools growing 

 adjacent to a known infested area. It is preferable to place the baits 

 on the soil between the banana rows or on tracks traversing the planta- 

 tion. Weevils have been observed to visit baits on hard, bare roads 

 and on the tops of standing tree-stumps. The corm or root stock 

 should be used for bait, and every trap should be examined once a day, 

 preferably in the early morning, the soil on which it has rested also 

 receiving close attention. The cut surfaces of the baits, if found to 

 be dry, should be pared, and should never be used for more than three 

 weeks at the most. 



Suckers that are to be used in estabhshing a new plantation should 

 be removed before nightfall on the same day on w^hich they are 

 separated and dried at some distance from the source, in order to 

 prevent infestation before they are planted. 



During mid- winter the adults emerge from the pupae in far fewer 

 numbers than at any other time. This, therefore, is the season when 

 old and infested stooLs should be eradicated and the ground cleared. 

 Even after this has been done traps should be laid on the cleared 

 ground, as it has been proved that weevils covered up in the soil.. 

 whether enclosed in fragments of the stool or not, may for many days 

 following the clearing of the land emerge and fly off to banana stools 

 in the neighbourhood. 



PicARD (F.). La Lutte centre la Cochylis par le Choix des Cepages 

 et par la Culture de Plantes attractives. — Le Progres Agric. et 

 Vitic, MontpclUer, Ixxv, no. 28, 11th July 1920, pp. 36-39. 



In response to an enquiry regarding the value of resistant varieties 

 of vines as a measure for guarding against the attacks of the vine 

 moths, Clysia ambiguella and Polychrosis hotrana, it is suggested that 

 the best method of preventing attack is not only to plant the varieties 

 that are least attractive to these pests, but also to surround these plants 

 vv'ith some food-])lant that is extremely attractive to them. it 

 is considered a great mistake to destroy all the preferred food-plants 

 of a pest in an infested region as a means of exterminating it, as this 

 merely has the contrary result of driving the pest on to the cultivated 

 crop. 



An analogy is drawn between the possibility of thus protecting a 

 cultivated crop by some more attractive food-plant, and the suggested 

 method of ])rotecting man from the attacks of mosquitos by surrounding 

 him with those species of animals that are preferred hosts [R.A.E., B, 

 viii, 141], or from ticks by the keeping of pigs. It is suggested that the 

 •common flax-leaved daphne. Daphne gnidium, plays in vineyards 

 the same role that the pig fills towards man. It is stated as certain 

 that a vine of some resistant variety, surrounded by a hedge of 

 D. grndiani would remain free from attack by P. botrana even in an 

 infested locahty, all the moths being attracted to tlie preferred food- 

 plant. In tliis way, P. hotrana, which is so difficult to destroy, would 

 be reduced to an inoffensive role. 



(701) c2 



