282 



THE AQKICULTURAL NEWS. 



■EITEMUEE, 



1919. 



INSECT NOTES. 



BEAN AND PEA WEEVILS. 

 (^Concluded.) 



The measures to be adopted to prevent injury consist of 

 planting only sound seed, thorough cleaning up at the end 

 of the crop, and treatment of peas and beans for the purpose 

 of killing the insects in them to prevent continued destruc- 

 tion in storage. 



Infested seed used for planting is likely to be the 

 means of introducing the weevils into the field. Badly 

 infested seed will either fail to germinate, or will produce 

 plants that are weak and incapable of making good growth 

 because of the loss of storedup food material which has 

 been eatpn by the weevil grubs. Seed intended for planting 

 may b.' dr pped into water, and the sound seed will sink 

 while that which is much infested will float. 



When the crop is harvested great care should be 

 exercised to collect all pods and seeds so that none shall be 

 left on the ground to furnish breeding places for the 

 insects, to enable them to tide over successfully the interval 

 between ciops. As soon as the crop is ripe the grain should 

 be harvested and the seeds shelled out of the pods, subjected 

 to treatment wliich will kill the insects contained in them, 

 and put up for storage in such a manner as to prevent 

 reinfestatioD. 



It must be remembered that even though all the insects 

 in such peas and beans may be killed, these seeds are 

 liable to reinfestation unless properly protected against it. 

 Weevils in peas and beans may be killed by applica- 

 tion of heat, fumigation with carbon bisulphide, or with 

 carbon tetrachloride. 



Carbon bi.'iulphide and carbon tetrachloride are similar 

 in all essential features, except that while carbon bisulphide 

 ia hii^lily inflammable, carbon tetrachloride is non-intiam- 

 mable. 



In fumigating with carbon bisulphide, seeds must be 

 placed in air-tight containers. Small quantities may be 

 treated in a kerosene tin or similar receptable, and for larger 

 (jnantities, barrels, puncheons or hogsheads may be used. 

 If the seeds are thoroughly dried they may be stored in 

 the same containers, where they may be examined from 

 time to time, and fumigated again if it is found necessary. 

 Carbon bisuljihide is used at the rate of 3 lb per 1,000 

 cubic feet of space to be fumigated, in a thoroughly tight 

 receptacle. If the receptacle is not tight the fumi 

 gation will give unsatisfactory results even if the dose of 

 carbon bisulphide is increased. The carbon bisulphide is 

 poured on to the top of the seed and the receptacle covered 

 with a tight cover. The liquid quickly vaporizes, and as the 

 fumes are heavier than air they settle into the mass of seed, 

 penetrating to every part and even into the interior of 

 injured sfcds. Fumigation .should continue for from 



twenty- four to forty-eight hours. Peas and beans are not 

 injured either for pl.inting or for eating by this fuiuigation. 

 The disagreeable odour of the carbon bisulphide passes away 

 when the seeds are thoroughly aired. 



The application of heat affords a useful and convenient 

 means of killing weevils in stored grains. Weevils in peas 

 and beins are killed by a temperature of 130° F. to 140° F. 

 for a few minutes. In dealing with a small i]uantity of 

 seeds they may be spread out in a thin layer and placed in 

 an oven. In the case of large quantities, as would be the 

 case if the entire product of a considerable acreage were to 

 be treated, a drying machine such as those operated by the 

 Government in St. Vincent and Antigua would be useful. 

 In such case a temperature of 140°F. for five to ten 

 minutes would be probably sufficient, since these machines 

 are so constructed as to allow all the seeds to become 

 thoroughly heated, and for equal l«igths of time. 



In the Southern States certain farmers have mixed 

 cowpeas which were being kept for planting with dry road 

 dusc or dry air-slaked lime. These substitutes do not appear 

 to kill the weevil in the seed, but they either prevent them 

 from emerging, or if they do emerge, from the laying of LH'gs, 

 and thus the continued attacks are stopped. 



NAPHTTiALENE^iToEiNi! i.'J SACKS, ETC. Naphthalene is 

 useful in connexion with the protection of peas and beans 

 and other seeds and grains from insect attack in storage. 

 Used in large quantity it acts as an insecticide and will kill 

 the insects in the seeds, and it also acts as a repellant and 

 prevents reinfestation. For the protection of stored seeds 

 lib. of naphthalene is said to afford protection for 40 bushels 

 of seed. The naphthalene is put up in cloth bags each 



containmg 



distributed in the mass of the grain. The 



naphthalene being in bajis, makes it possible to recover any 

 that has not evaporated, and considerable saving is thus 

 effected. Fairly tight receptacles are necessary for the us* 

 of naphthalene to give best results. 



While there is bo doubt that the weevils which attack 

 peas and beans cause serious losses, yet it is certain that 

 much may be done to reduce the amount of these losses. A 

 further development of kiln drying as a means of condition- 

 ing grains and .seeds of all kinds in these islands should give 

 a sense of security to growers who wi.sh to increase the 

 amounts of leguminous and other food grain, since it should 

 allow for the treatment of seed before storage, while proper 

 storage combined with this should reduce the losses from 

 weevils very considerably. 



CASUARINA AND MANGROVE BOTH 

 ATTACKED BY THE SAME BORER. 



According to an article in the Journal of Economic lie- 

 search, Washington, 1) V., Vol. .VVI No. 6, the casuarin* 

 which has been extensively planted in Florida has been 

 seriously attacked by the mangrove borer {Chrvsolmlhris 

 tranijueharicn, Omelin). ( 'iisnarina is a tree of much value 

 for planting in the West Indies, and deserves to be more 

 used than it has been in the past ; the mangrove and iis 

 borer occur in some of these West Indian islands. On this 

 account the article mentioniid is summarized herewith for 

 the benefit of readers of the Agnciiiiurd/ iVejvs. 



The red mangrove (Rhizo/ihora maiig/e, L.) is a native of 

 the West Indies and perhaps also of Florida. The man- 

 grove borer, also a native of the West Indies, is recorded as 



