2G 



THE AGKICULTURAL NEWS. 



Jaxvakv 15, 191(j 





'61 



INSECT NOTES. 



being scattered lightly on the ground where the beetles are 

 at work among the plants. 



This remedy vvofild .seem to be worlh trial in conjunction 

 with clean culture,' lor the Myochrous beetles and for the 

 bronze beetle (Colaspis lastidiosa) in St. Vincent, and it 

 might be etfective also in the case of the weevils of the 

 genus Lachnopus. which have attacked cotton seedlings in 

 Anguiila and Antigua. 



H.A.B. 



THE CORN LEAF BEETLE. 



In the report of the liarbadus Department of Agriculture 

 for 19 12-1 .3, an account was given Of the Corn leaf weevil 

 (Myochrow; at iiiatus) as a minor pest of sugarcane and 

 Indian corn in that i-sland. 



This insect has been known in Barbados fnr .-evcral 

 years, but has never become a serious pest. A related 

 in»ect is reported as being a serious pest of Indian corn in 

 certain sectifins of the United States. It is called the 

 Southern C<<rn leaf beetle (Myochrmis rienticollif). This 

 latter insect is recorded as occurring in Grenada, although 

 so far it has not been reported as a pest. A related insect 

 in St. Vincent is Colaspis faslidipsa, which has been at times 

 very troublesome, from its habit of attacking very young 

 cotton seedlings. These insects are not weevils; they belong 

 to the Chrysomelidae, the leaf beetles, so called because the 

 adidts, and, in many instances, the grubs also, feed on the 

 leaves of plants. The adult beetle (Mi/ochro'is (irmatus) in 

 Barbados is known to attack the leaves of sugar-cane plants: 

 they probably eat the roots of these and those of the Indian 

 corn as well. 



The )Soutbern Corn leaf beetle {Mpochrous deni icoUis) in 

 the United States attack.s the roots of Indian corn and of 

 several other plants when in the larval stage, while the adults 

 eat the leaves of the corn plants, often causing the loss of 

 practically all the plants over considerable areas. These 

 attacks usually occur in the early spring when the corn is 

 young. 



It appears that the adult beetles hibernate in and near 

 the corn fields, taking advantage of the presence of weeds, 

 trash, and other rubbi.sh to provide suitable protection from 

 the weather. 



The clearing u)) of all lubliish, and n(jt allowing fields 

 to lie idle and grow crops of weeds near the cultivations, 

 •would seem to offer a satisfacKjry means of reducing the 

 numbers of the beetles. 



It has been found that early planted corn may be 

 severely attacked, and that wh'fn the damage to this is so 

 severe as to necessitate replanting, there is no second attack 

 by the beetles on tiie same land in the same season. This 

 .suggests that in the West Indies when attacks of these 

 beetles have occurred, and repetitions are feared, a trap 

 crop of corn, or other favoured food, might be planted, and 

 when the attack has developed the trap crop might be 

 removed and the real crop for the season then be planted. 

 Clean cultural methods also would le as profitable in these 

 islands as in the United States. 



As a direct remedial me.'Vsure it has been found that 

 a poisoned bait con.sisting of 2.5 tb. wheat bran, or jxillard, 

 1 111. Paris green, 1 gallon molasses, and ihe juice of three 

 oranges, with enough water added to make a stiff dough, is 

 effective. 



Tlie best success in the use of this poisoned bran bait 

 was obtain<'d when applied late in the affernnon, the bait 



The Storage and Use of Soil Moisture. —The 

 results of field studies of soil moisture accumulation and 

 conservation, conducted for six j-ears on fairly uniform fine 

 sandy loam soil at the North Platte (Nebraska) sub-station, 

 are reported. 



Under field concUtion.s, the ma.\imum capacity for water 

 of the .soil in question was found to be from 16 to 18 per 

 cent, of its dry weight, of which that above 7 to 8 per cent, 

 is available for plant use. The more important findings are 

 summarized as follows :-- 



Summer tillage is the most effective means of 

 storing water in the soil, the annual storage by thi.s 

 means varying from 10 to 33 per cent, of tiie seasonal 

 rainfall, according to the amount and distribution of 

 the rainfall, the effectiveness of the tillage, and the 

 presence or absence of a growing crop. Ploughing seems 

 better than disking .for accumulating water in the soil, 

 although disking small grain stubble to kill weeds and stir 

 the surface is generally effective. Artificial mulches of 

 straw or hay are more effective than soil mulches in absorb- 

 ing and retaining rain-water, and a 3-inch mulch is more 

 etfective than a shallower one. Corn, oats, spring wheat, 

 and baifey use water from the first -1 or 5 feet of soil, winter 

 wheat at a depth of 6 or 7 feet, and alfalfa and grasses when 

 well established, at much greater depths. Under normally 

 favourable conditions growing vegetation is a greater fac'or 

 than surface evaporation in removing water from soil, and 

 weeds are fretjuently the most effective agents in removing 

 available w-ater from soils, and in preventing the 

 storage of water for the use of other plants. Capillary 

 movement is feeble in .soils that are dried to any 

 considerable e.xtent below- the saturation point, so that in 

 the main, the plant roots to obtain water extend them.selves 

 into the soil where available water is present rather than 

 depend upon capillarity. 



In order to store water in these .soils it is necessary that 

 the soil surface should be in condition to catch rains, and 

 kept loose and rough by cultivation to reduce evaporation 

 and prevent blowing. Weeds should be suppressed, as far 

 as po.ssible, before and after seeding. Crops which will 

 withstand considerable drought or escape drought by matur- 

 ins early should be chosen. (The Experiment Station Recvil, 

 Vol. .X.K.XI, No. o.) 



.-V useful suinniary of ihe position of bovine tuberoulosis 

 in man has appeared in the form of a piper recen ly issued 

 in ihe lieadirni L'nrveistti/ Colleye Reritir. On lie basis 

 of slalis'ics obtained in Mancliester, it li-s been found ihat 

 the bovine type of tubercle bacillus is the cause of a* out 

 one-fourth of the cases t<i other tuberculous diseases at ag^'s 

 up to si.xteen, that iWi to say, about 3,()(K) de^ihs per year. 

 If this be so, bovine tuberculosis i.s responsible for 30,000 

 cases of illness at any one time. 



