•218 



THE AGKICULTURAL NEWS. 



July U, 1906. 



INSECT NOTES. 



Cotton Stainers. 



The last issue of the West Indian Bulletin 

 >(Vol. VII, no. 1) contains a valuable paper by 

 Mr. Henry A. Ballon, B.Sc, Entomologist on the start' 

 of the Imperial Department of Agriculture, on ' Cotton 

 Stainers.' The following extracts are likely to be of 

 interest and give some idea of the scope of the jxiper : — 



The cotton stainers of the genus Bi/sdercini are widely 

 distributed in the cotton-growing districts of the world. 

 Although a great many species have been catalogued and 

 described, very little has been done in recording their habits 

 and life-histories. The notes on habits and life-histories 

 embodied in this paper have been made in the laboratory 

 of the Imperial Department of Agriculture at Barbados 

 on insects in captivity, which have been received from the 

 other islands, or have been reared from eggs produced by 

 such insects. 



The present paper contains descriptions of the species 

 known to occur in the Lesser Antilles and Trinidad, a li.st 

 of the species fi'oni tropical and subtropical America, and 

 references to publications in which these species are described 

 or catalogued. Two species and one variety, believed to be 

 new, are described, and notes are added on life-histories; 

 habits, food plants, and on geographical distribution. 



In the British colonies of the Lesser Antilles, two 

 species of Di/fcfercus have been recognized : D. andreae, 

 Linn., in the Northern Islands, and £>. aniudi-jer, Uhler, 

 in the Southern Islands. In the French Islands — Martinique 

 and Guadeloupe — D. chlauveyi, Lethierry, has been recorded. 



Specimens of D. andreae that have been e.vaniined show 

 little variation, either in specimens from the same island or in 

 those from the different islands. Specimens of D. aiimdiger 

 that have been examined show that variations in colour, 

 in addition to those indicated by Uhler in the original 

 description, occur in specimens from the different islands. 



Comparisons of the descriptions of D. aiinulif/er and 

 D. delauneyi, and of these with the specimens, indicated that 

 the.se names were synonymous. Since the description of 

 D. delauneyi was published in 1880, and that of D. annul i(/er 

 in 189-1, the name of B. delauneyi should stand, and 

 I), annuliger be sunk as a synonym of it. 



Two species, believed by Mr. Ballou to be new to 

 science, are described as Dijsdercus fervaldi (found in 

 Grenada) and D. koivardi (found in Trinidad); also 

 ii new varietj', D. liotvardi, var. minor, which also 

 occurs in Trinidad and was taken on cotton plants with 

 the species. Notes are also given on the life-histories 

 of the different species. 



In regard to food plants, Mr. Ballou states, infrr 

 idia : — 



The species of Dysdercus are known chieHy as pests on 

 cotton, which seems to be the preferred ftiod. In addition to 

 cotton, the West Indian species feed upon the seeds of the 

 .silk-cotton tYee{Eriodendron anfrartuoszan), on okra IJfdji.'^cK.i 

 eKCulentus), on musk {I/ihifcuf Ahelmoscims), and probably on 



other malvaceous plants ; perhaps, also, on plants of other 

 orders, although actual observations are wanting on this point. 



Full information is also contained in the paper as 

 to the damage done to cotton, the remedies to be 

 adopted in dealing with cotton stainers, and so forth. 



Although cotton stainers have been known as pests for 

 many years, not much has been done in developing insecti- 

 cides or control measures for dealing with them. 



In the West Indies two methods have been u.sed with 

 success. One of these consists in attracting the insects to- 

 baits, and killing them with hot water or kerosene. Cotton 

 .seed or pieces of sugar-cane, [ilaced in small hea|>s at frequent 

 intervals throughout the field, have been used for bait. 

 Cotton seed seems to be nnich preferred to sugar-cane, and,, 

 scattered about the ginneries, it attracts large numbers of 

 these insects, and may be made to serve as a trap. This 

 method is likely to give best results ' between crops ' when 

 there is not much attraction for the insects on the plants. 



During the flowering and ripening period, however, the 

 practice of collecting is likely to give the best results. At 

 this time the insects, young and old, are to be found on the 

 cotton pilants, and are frequently congregated on the bolls 

 and tips of branches. The method of collecting is this — a 

 bucket or kerosene tin, containing a small amount of water 

 and kerosene, is used for catching the in.sects, which are 

 shaken or jarred oft' into it, the film of kerosene killing 

 them quickly. 



Mr. Ballon's remarks on the distribution of 

 cotton stainers may be summarized as follows: — 



The genus Di/sdercus pi'eseuts some peculiar conditions 

 in geographical distribution. D. andreae is recorded from 

 the Greater and the Lesser Antilles. It occurs in an unbroken 

 series, with the e.xception of Porto Rico, from Cuba, its 

 northern and western limit, to ilontserrat, its southern and 

 eastern Hunt. Montserrat and Guadeloujie are shown to 

 have both /-*. andreae and D. delauneyi, while from Dominica 

 to the Grenadines only one specie.s, D. delauneyi, occurs in 

 each locality. In Grenada Z>. fernaldi and D. delauneyi 

 occur, and in Trinidad D. howardi and its variety minor ;. 

 while in Tobago only D. howardi is known. 



Cotton Worm Season. 



Reporting on cotton cultivation in Nevis ia 

 February last, the Agricultural Instructor mentioned 

 that many planters were resolved to begin their plant- 

 ing much earlier this year, 'so as to have strong mature 

 plants before the " worm season " begins, as the older 

 plants seem better able to withstand an attack than 

 the young plants.' 



In reference to this, Mr. Henry A. Ballou, 

 Entomologist to this Department, wrote the following 

 iiiemoranduni : — ^ 



In regard to the ' worm season' referred to above, I may 

 say that there is a very general popular belief that the worms 

 (cotton worms and other caterpillars) come only at given 

 seasons. The season of abundance with these insects seems 

 to depend on the amount of suitable food and the weather 

 conditions. These conditions are generally found at certain 

 seasons, but the experience of last year with the cotton 

 worm shows that there are no well defined seasons. Many 

 planters said that there would be no worms after November 

 and December, but in .lanuary 1905 they were quite abund- 

 ant in Barbados, .January being ' out of season.' 



The matter of planting with reference to a ' worm season' 

 is not, in my opinion, likely to give any practical results. 



