186 



THE AGRICULTURAL NEWS. 



June 6, 1914. 



INSECT NOTES. 



INSECT PESTS IN BARBADOS, 1912-13. 



IL 



The female Phytalu.? beetle deposits her eggs singly at 

 a depth of from 4 to 6 inches in the ground; the life-cycle 

 occupies from 26.!) to S-'JS days from egg to adult. The adults 

 are most abundant in May or June : they are not much at- 

 tracted to light, though sometimes they fly into houses and 

 are caught in light traps. 



Tiphia parallela is a very efHcient parasite; its life-cycle 

 -occupies a period of about fifty days, and each female prob- 

 ably produces about seventy eggs. The Tiphia female bur- 

 rows into the ground in search of the Phytalus grub, and on 

 finding one, stings it into temporary in.sensibility, and lays 

 an egg upon it, attaching the egg to the dorsal surface of the 

 thoracic region. After a short time, the host recovers from 

 the effects of the sting, and resumes its feeding and accus- 

 tomed movements. In about five days the egg of the parasite 

 hatches, and the larva penetrates the skin of the host with 

 its mouth parts and begins to feed, growing rapidly for the 

 first few days. In about ten days, the hard back grub suc- 

 cumbs to the eft'ect of the feeding of the parasite, which then 

 feeds vigorously, clearing out the skin of the host in a few 

 hours, and more than doubling its own size in that time, 

 after which it spins a cocoon and enters upon its pupal stage, 

 which lasts from thirty to forty days, the average being about 

 thirty five. 



The adult Tiphias are not flower visitors, but feed on 

 honey dew, on plants infested with Aphis and other similar 

 insects. This insect does not seem to be generally distributed 

 over the island, as shown by the occasional outbreak of Phy- 

 talus in numbers, when, in certain cases, no Tiphias were to 

 "be found. 



The ordinary hard back (Liyyrus tuntulosus) has been 

 .found to be parasitized by Dielis dorsata in much the same 

 way as in the case of Phytalus already mentioned, the chief 

 points of difference being that the sting of the Dielis female 

 produces a degree of paralysis from which the Ligyrus grub 

 does not recover, and that the Dielis egg is deposited on the 

 ■ventral surface and not on the dorsal, as is the case with 

 Tiphia. 



The Dielis wasps both male and female visit flowers. 

 The species is parasitized by a Rhipiphorid beetle, which also 

 is found in and about certain flowers. The common hard 

 back is not known to attack plants, the grubs being found 

 in manure, rotting megass, etc., while the adults are not 

 known to feed at all. The rate of parasitism by Dielis is 

 not very high. 



The cane fly [Delpha.r saccltarivoi-a) is reported to have 

 attacked both old and young canes. The attack was but 

 -of short duration, the insect apparently being controlled by 

 •natural enemies, principally the lace wings {Chrysopa spp.). 

 The rust mite of canes {Tarsonentus spinijies) is reported of 

 general occurrence but apparently it caused no damage to the 

 -canes. A small coccinellid beetle was found commonly 

 Among mealy-bugs on sugar-cane and was supposed to be 

 j)redaceous on them, but this point is not determined. 



COTTON PE.STS. The leaf blister mite of cotton {Erio- 

 phyes gossypii) is stated to have spread to all cotton- 

 growing areas of the island, and to have become a very 

 serious pest. The system of allowing cotton to remain 

 in the land for .second and third pickings and often 



until the new crop has been planted infests the new 

 crop directly from the old. The writer of the report 

 is of the opinion that the enforcement by law of the 

 removal of all old cotton before the season for replanting 

 is the only way to reduce the leaf-blister mite to negligible 

 proportions and that under Barbados conditions this offers 

 a fair chance of getting rid of it entirely. Cotton plants of 

 the 'native' type growing among infested Sea Island show no 

 signs of the presence of the mites. 



.SWEET POTATOES, ETC. These were attacked by thrips 

 (Eathrips .'p.), flea beetle (C'/iaetocnema ama:oiifx), and a red 

 spider [Tetram/chus telarius). These three pests usually 

 work together, generally being much worse io dry weather. 

 It is recommended that slips for planting should be fumi- 

 gated in a tight wooden box or a puncheon by means 

 of carboQ bisulphide at the rate of 1 dram to each cubic 

 foot of space, in order to prevent the introduction of these 

 pests at the time of planting. 



The cassava hawk moth {Erinni/is [Dilophonota] ello) 

 occurred as a pest in a severe attack on fields of cassava 

 re.sulting in the complete defoliation of the plants over an 

 area of about 12 acres. Four broods of caterpillars were 

 observed; these occurred at intervals of thirty days. It is 

 estimited that there were eight broods during the season. 

 Spraying with arsenate of lead and dusting with Paris green 

 were found effective measures in controlling the caterpillars. 

 In spraying, the arsenate of lead was used at the rate of 4 ft). 

 to .50 gallons of water, with molasses added at the rate of 

 1 pint to the gallon. This was found necessary in order to 

 overcome the water-repelling quality of the cassava leaves. 

 The Paris green was used at the rate of 1 Mb. to 6 B). of lime. 

 The caterpillars and pupae were eaten by the Barbados black 

 birds {Quiscalus Jortirostr'is), the caterpillars by the wild bees 

 (Polistes spp.); the moths were captured by the rain bird 

 (Tyrannus rostraUis). A remarkable feature was the entire 

 absence of Tachinid flies or other parasites, as far as could be 

 seen. 



The whitewood moth (Duoruitus punctifer). The larvae 

 of this moth were found tunnelling in whitewood (Teconia 

 leucoxylon); it was afterwards found in sour sop {Anona muri- 

 cata), in Barbados cherry i Malpighia glabra), in the woody 

 stems of Ipomoea vines, and in ornamental crotons (Codiaeum. 

 spp.). 



SCALE iNSECT.s. Species of the Coccidae recorded during 

 the year as being of interest are Asjndiotus [Chrysomphalus] 

 howi-eyi, Ckll., on agaves, Aspidiotus [Pseudaonidia] tessera- 

 tiis, De Charm., on Cassia Fistida. Another scale closely 

 resembling the last named and probably a new variety was 

 found on grape vine and Vitis [Cissus] sicyoides on the 

 former of which it is capable of doing considerable damage. 

 It occurs under the bark causing great numbers of small 

 swellings. CMonaspis unilateralis, Newst.. on a palm 

 (Thrindx) is a new species. Lecanimn hesperidum has been 

 identified as occurring on Phichea odorata and on seedlings of 

 Sterculia fulgens. This is of interest since the original 

 records of L. hesperidum, in Barbados and other of the 

 Lesser Antilles as abundant and injurious, probably referred 

 to Lecaniuni viride (Coccus viridis), while L. hesperidum. was 

 and is a rare insect. 



An experimental plot of papaw was severely attacked 

 by leaf hoppers of the family Jassidae, apparently the same 

 species which occurs on cotton without appreciable injury to 

 the plant. The damage to the papaws was severe and the 

 plants were sprayed with resin compound; the attack was. 

 checked but reinfestaiion soon took place. 



