10 



THE AGRICULTURAL NEWS. 



January 11, 1918. 



INSECT NOTES. 



ENTOMOLOGY IN JAMAICA. 



The Annual Keport on the Department of Agriculture, 



the 

 the 



Jamaica, for the year ended March 31, 1918, conUins^among 

 other matters the Annual Keport of Mr. A. U. Ritchie, 

 B. A.. Entomologist, as Section VIII. The body of 

 ceneral report was reviewed in the previous number of 

 A-ruultural y.-vs. The following is a summary of the sec 

 tion devoted to the report of the Entomologist. 



During the year the complaints of the depredation of the 

 sweet potato weevil {Cxhxs formicarim) have been more 

 numerous than usual. This increased prevalence appears to 

 be due to the lack of care in selecting material for planting 

 Small potato roots, used to form a nursery to provide slips 

 for planting, furnish sound plants. Young tips of vines are 

 much more free from infestation than old and hard portions 

 of the vine, and they also give a better yield in the subse- 

 quent crop 



There seems to be no care or judgment used in this 

 matter on the part of many; old and even infested vines were 

 seen used for planting. 



A strict rotation of crops should be practised, and 

 greater care is necessary in the disposal of weevil-infested 

 potatoes when the crop is harvested. It is often found 

 imposMble to allow the crop to mature fully on account of 

 the rapid increase of weevil injury as the crop is ripening. 

 This is estimated 10 be greater than the increase in weight 

 ot roots in the same time, and consequently the crop should 

 be lifted as soon as the weevil attack is observed. 



It is judged that a useful line of experiment would be 

 that of endeavouring to produce a short crop variety — one 

 which would ripen early with fair yields, especially for use 

 in districts where the wet season is short, and the dry sea.son 

 imposes a check on the plant. 



In localities where the .sweet potato weevil is a pest, 

 sweet potatoes can be expected to give crops, (a) if the natural 

 or cultural conditions are such that the crop makes steady 

 growth, without checks or setbacks; (b) if careful selection is 

 made of plant material to provide the best slips and those 

 free from weevil infestation; (c) if careful attention is given to 

 the general ."anitation of the fields; and (d) if rotation of crops 

 is practised year after year. 



The Entomologist refers to the new weevil of sweet, 

 potatoes, Valaeopus costkollis, and that of the yam, Valacopiis 

 dioscoreae, mentioned in the Agrkiilliiral -Airt's (Vol. .XVII, 

 p .346), and adds another to the list of sweet potato pests. 

 Eiiscep'es pom //lis, which had not been previously recorded 

 in Jamai'ja. 



Other sweet potato insects mentioned are a scolytid 

 beetle, Hypo/ltoutnus ri/chici, a new species found to be 

 injurious to dried potato chip.s which were prepared for the 

 manufacture of sweet potato flour; the sweet potato leaf-folder 

 (Pi/ocrocis tripuiic/a/a. Fab.), which is occasionally destruc- 

 tive in sweet potato fields in Jamaica; and Mi/rimi'i 

 propiiiijiia, one of the tortoise shell beetles, which occurs in 

 small numbers. 



The yam 8ca.\e {/Ispii/io/iif /lar/ii) \a recorded as .some- 

 times killing out the yam plants. Badly infested roots used 

 for planting are the .source of .■scales which attack the young 

 vine. The remedy is to dip the yam heads before planting 

 in strong lime-sulphur, 1 gallon concentrate (32" Reaunu) 



to 10 gallons of water, and allowing this to dry thoroughly. 

 Infested vines should be burned after the crop is harvested. 

 The yam weevil (Pi'/aenpus t/insrotrae) has been mentioned. 

 Attention is called to the prohibition by the United 

 States Government of the importation of yams and sweet 

 potatoes grown in Jamaica, owing to the prevalence of the 

 weevils Cy/iis formiciriiis. and Eiiscepes l>atn/iie. 



The greatly increased production of field peas has been 

 accompanied by extensive losses from the attack of the 

 weevils Britdius phaseo/i, and B. rjuadrimacii/atus in the 

 fields Bnd in storage. 



Peas should be planted at such a time as will provide a 

 quick growing season, and a dry ripening period. The crop 

 should be gathered at once when it is ripe, and the beans 

 treated immediately to destroy the weevil life in them. 



This may be done by sun drying, in a machine for the 

 application of artificial heat, or by the use of carbon bisul- 

 phide. The peas should then be stored in tight bins or other 

 receptacles to prevent reinfestation. A kerosene tin full of 

 peas may be successfully treated by introducing a teaspoon- 

 ful of carbon bisulphide, covering down, and allowing it to 

 remain for twenty-four hours. 



'There is no method of field treatment, and control rests 

 in proper and immediate care of the crop.' 



Cut worms were much in evidence, especially in reclaimed 

 land hastily prepared for food crops or sugar-cane. Such 

 lands should be thoroughly cleared of all weeds and bushes, 

 and either fallowed for four to six weeks before planting, or 

 given an application of poison bait. 



Indian corn uas attacked by the usual pests, the boll 

 worm {He/iotliii obio/eta), and the corn ear worm {Lap/iygma 

 friii^iPerdti). The following are given as protections for the 

 young plants: (a) mix a little over I teaspoonful of Paris 

 green in 1 quart of corn meal till all has a green tinge; 

 sprinkle a pinch of this in each uncurling corn heart; (b) dust 

 arsenate of lead and wood- ashes in equal parts, or Paris green, 

 road dust, white lime, or wood-ashes, 15 parts, lightly 

 from a fine muslin bag into the corn heart; (c) arsenate of 

 lead as a wet spray, J lb. to 4 gallons of water, can be 

 applied with force into the corn hearts from a tin mist 

 spray- r with a quart container; (d) hand picking has given 

 good results; (e) ground cultivation with a scuffle hoe 

 will expose the pupating forms to sun and natural enemies; 

 the caterpillar changes into the moth in the soil at the base of 

 the corn plant; (f ) a well prepared and rich seed bod will 

 greatly favour the quick establishment of the plants, and 

 take them beyond the point when the worms may eat out the 

 growing tip of the corn plant. 



Corn weevil ciuse.s some loss, but this can be largely 

 prevented by quick and thorough drying on the cob when 

 the crop is gathered. Shelled corn should be stored in tight 

 bins, as in the i aso of peas. The ajjplication of heat, and 

 the Ufe of carbon liisulphidc have the same beneficial effect in 

 the case of corn as with peas. 



The cultivation of rice in the Westmoreland district, as 

 a war measure, directed attention to certain insect problems 

 connec:ed with health and sanitation. 'Satisfactory drainage 

 and water control in districts where rice is being grown, besides 

 ameliorating the malaria and moscjuito situation, would 

 greatly assist in the control of liverfluke of cattle, and 

 certain Tabanidae m- horse flies. The water snails concerned 

 as intermediate hosts of tluke would be deprived of consid- 

 erable areas offering breeding conditions — conditions which 

 are also suitable for the maggots of horse Hies which at times 

 become a plague in the region of the morass.' 



(To /'(• continued-) 



