TIIK AGRICULTURAL STEWS. 



Febei \ky 21 



1915. 



INSECT NOTES. 



AGRICULTURAL PESTS, NIGERIA. 



An interesting re] Itural Pesl ol the 



Southern Pro "\ Vf. A. Lamborn, M. I!., is 

 published in 



Eni Part The following is 



:i brief review of this report, with special reference to those 



points which li.' to West [ndian conditions. 



The insects and mite pi dealt with under crop headings, 



the three pi incipal "' ■■..,. ao, and maize. 



The pests named as attacking the leal of the cotton pin it. 

 are a leaf miner, the larva ol a small Tineid moth {At 

 bifateiata, Wlsm ). a small mite, probably a red spider of the 

 i 'ni aphis (Aph is gossupii, Glov.), 



bort horned grasshopper (Zonocerus variegatus, I.... the leaf 

 roller (SyleptaderogataJ?.), the larvae of the Limacod moth 

 (Parasa imfuscata, Wichg. ,andofa Noctuid moth, as well as 

 certain I I roong them a Lagrid (Lagria villota, I''.), 



:iml an Eumolpid (Syagrus calcaratus, F.). 



The leaf minei at time can es considerable damage b} 

 redu< ing the vitality "t the plant. 



The small mite or red spider i- suspected of being 

 instrumental in tin- spread "t 'black ami, and of a pink 

 Fusarium, but the point is not considered t" be proved. 



Thf cotton aphis wiii- abundant in August but they 

 were quickly and effectively i becked bj their natural enemies, 



among « hich were three lady bird beetles, the Ian f three 



species of Syrphus Bies, and the larvae of a lace wing. The 



lady-birds were Chilomenes lunata, ¥., Chilomenes vicina, 



Is., and Hyperaspis pumila, Muls.; the Syrphid Hies were 



nasutus, Wied., Paragua borbonicus, Mcq., and 



Paragus long . Bezzi; the lace wing was Micromus 



tunidus, II igen. I'.\ far the worst pest attacking the leaves of 



cotton plant was the shorl horned grasshopper, the nymphs 



of which appeared in immense swarms in November, and i d 



tirfly defoliated man] plants. Although cotton was the 



favourate f 1 plant, these grasshoppers appeared to feed on 



many others, including wild bush plants, and cultivated crops 

 such as maize, young Para rubber, cassava (in particular), 

 cacao, bananas, and a varietj of ornamental plants, especially 

 Acal} ]'li i 



An attempt to control this insect was made bj spraying 



with lead chromate, but it appeared to kill but few of them, 



serving more a deterrent, which drove them to other 



its. The leaf roller was abundant at one part of thi reason, 



rticularlj on certain imported varieti >< ! cotton, chiefly 



American. This insect wa somewhat held in check by 



Hymenopterous parasites, Xanthopimpla punctata, and 



others, and Tachinid flies, ol perhaps two species. As this 



control was not effective, n iorl was had to hand picking by 



! cted at the same time the various 



cotton stainers. The othei insects attacking the cotton 



much damaj 

 The tl cotton stem were two 



ttpis minor, Maskell, and 

 /■„ . wsteud; and a small green Buprestid 



I. |, Thi -e.de insects were 

 not on i icularl} abundant or injurious. 



The lai vae of the be i ai ted considi 



by .1 ri i the stems ol the plani ■. w bi 



plants much distorted and 



Thej did ill} die but pi duced later, 



lerfect, undersized bolls. Older plaid-, when attacked, 



ii i ; ■ il :. shedding theii leaves. 



Tic larvae tunnelled and fed in the layers ■■!' young tendei 

 wood just beneath the bark until fully mown, when they 



I :t rated into the pith, where the} pupated. The adults 



d l'\ borin» their way out, ' ; big holes being 



visible high u| the main stem or large branch 



The roots Ol the cotton plant were attacked by the 



lai vae ol a Li ■> a bt • 1 1 i ; some injury was done by 



Carbon bisulphide was tried as a remedy with 

 promising result: The plot of cotton attacked by these 



hard back grubs had 1 n planted in cotton in the previous 



and it is i h night that this accounted for the d 

 done; a ro I crops might have been a better plan. 



A considerable number ol insects attacked the cotton 

 bolls. Of these there are two boll worm- which attack the 



i lature lint and seed in unopened bolls, and two which 



confine their attacks to the seeds both in "pen. .1 bolls, and in 

 storage 



The two boll worms which attack the unopened bolls an 

 the cotton boll worm {Eria t, Walk.), and the \ 



worm | Diparopsis castanea, limp. ). These w ■ re of abundant 

 occurrence, the former of them being controlled by a hymenop- 

 terous parasite. 



In the case of the other two boll worms, Pyrodt 

 s,injil- r, Wlsm.. and Mometa zemiodes, the larvae are small, 

 bright pink caterpillars, which attack cotton seed in the open 

 bolls in the fields, and in storage both efo fterginning, 



and the} are also found in waste cotton scattered about the 



gi ay. The larvae of both these species are attacked 



by a Chalcid parasite (Ckalcis olethrius, Waterston). 



Four species of cotton stainers were observed, viz. 

 Dysdercus superstit iosus, F., D. nigro-fasciatus, St.d., D. 

 melaiioderes, Karsch. and Oxycarentis ditdgeoni, Dist. 



Of these, i ii 1 1\ the first named was at all numerous. This 

 species was found "ii a variety of food plants of which okra 

 was the favourite The insect fed in numbers on the nectar 



of Urtna lobata, and was even observed on a dead and 



sun dried lizard, and on sheep'sexen ta 



It is stated, as a fact of interest, that D. superstitiosus 

 and I). Melaiioderes have been observed to interbreed. 



Hand picking nn.- to lie tin most effective method ol 

 control for the cotton stainers. 



The pest- which are reported a- att icking the cacao leaf 

 were a species ol Psyllid (Udamostignia tessmanm, Aulm. 

 -.ii. i, on the growjtrg shoots of young plants; they were 

 controlled by brushing with kerosene emulsion; Aphides, on 

 the leaves and young pods, which were controlled by natural 

 enemies; the grasshopper, already mentioned as a pesl ol 

 cotton; a Rutelid beetle (Adoretus hirtdlus, Castn.), which 

 was the worst cacao pest. This i eeds by night oi 



young plant- and hide- by day. Xe\t in importance as 

 a pest of this crop is the Arctiid moth I D\ < iculosa, 



Cram.). Several other insects att ick the leaves of cacao, l>ut 



thej a f minor importance. It is an interesting fact that 



the leaf-attacking pests of cacao are mostl} to be found on 

 trees. The older trees are frequented b} the red tree 

 ant (Oecophylla iragdana longinoda, Latr.), which is 

 highl} combative, and probably keeps off man} pests, as 

 these an not attacked; while thi younget plants which are 

 not frequented b} this anl suffer, sometimes severely, from 

 2 ins* cts. 



Pai lime, dusted on the leaves of the yi 



i .■■ ults iii the i I ol insects, but as 



bi iwed a tendenc} to scorch the \ oung I 

 lead chrom i i spra} . wasaftei wards used. 



This article will be concluded in th lie of the 



Agricultural -V 



