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THE AGRICULTURAL NEWS. 



March 13, 1315. 



INSECT NOTES. 



AGRICULTURAL PESTS, NIGERIA. 

 II. 



The following is a continuation of the abstract oi the 

 report on insect pests in Nigeria, Southern Provinces; the first 

 part appeared in the I ist iss f the Agricultural News. 



. V0 coxa l\i Kl>. 



The sinn of the cacao plant was attacked by the larvi I 



the moth, Eulophonotus myrmeleon, Feld., the only repi 

 tative of the family Megalopygidae known to occur outside 

 the American hemisphere. This is the only cacao borer found. 

 It tunnels in the medium sized branches, rarely in the main 

 stem. The attacked branches drop their leaves and even 

 tually die. 



The common method of dealing with this cacao 1 ir 



is to cut off the <k'a<l and dying branches, and to leave them 

 cm tlic ground. This probably does not kill the borers 

 to accomplish this, the infested branches should be burned. 



The boring larvae may be hilled in the branches in the 

 railv stages of the attack by probing the tunnels with a flexi- 

 ble wire, or by injecting carbon bisulphide into the tu 

 and plugging the opening with damp clay. 



The hark sapper or rind hug (SaMbergella theohr 

 Dist.) has occurred in certain districts as a serious pest, and in 

 others in small numbers. 



The scale insects attacking cacao in Southern Nig 

 are not serious pests. They include one or more species <\ 

 Dactylopius, Stictocoecut ajiisteadi, Newst., and Stict 

 dimorpkus, Newst. The latter is a recognized pest of pigeon 

 peas and probably invades the cacao to a slight extent 

 that plant, which is commonly osed as a shade plant. In 



addition to these is a species of [cerya, which was c mon 



on pigeon peas, and also occasionally found on cacao. 



The species oi Dactylopius are common]} held in c] 

 in Nigeria by the larvae of a Lycaenid butterfly (Spalgis 

 lemolea, II. H. Druce). On small plants the Dactylopius 

 scale i- treated also by being brushed over with kei 

 emulsion. 



The cacao pods were attacked by only a few insei 

 and very little damage was done by them. 



Termites are numerous, eating away the dead wood of ca< 

 trees. Thej were not found eating away living wood, hut i; 



is 1 ikil \ that as the dead w 1 i- eaten the live wood dies faster, 



and thus their action hastens decay. Dead plants on native 



farms are not often removed until they bee infested with 



termites, and frequently no other cause was to be seen to 

 account toi the death of the tree; hut it is stated that these 



insects follow clos i fungus attacks, and perhaps trees 



dying from fungus diseases are attacked bj termites, and 

 their death hastened. 



The termites were successfully combated by the use ol 

 •Universal Ant Destroyer' a machine by means of which 

 sulphurous and arsenical vapours, with a mixture ol carbon 

 monoxide and dioxide, are pumped into the termitarium. 

 (An account of this machine was given in the Aiinrtiiinr.il 

 News, Vol. XI, p. 122.) 



The leal eating pests attacking maize are not num. ro 

 the most important being lepidopterous larvae. The life- 

 history of one of these lepidopterous insects (Prodenia 

 litura, F.), was worked out. The female parent moth 

 deposits her eggs en masse on the underside of thi 

 leaves, protecting and concealing them with hairs and scales 



from her ibdonu n. The larvae hatch in about three days and 

 attain full growth in about three and a half to four weeks. 

 The pupa stage lasts about eight days. When the larvae 

 1 1 o .ut two-thirds grown they conceal themselves in the 

 hi art ..t the plant, and it is at this time thai greatest dam _ 

 is done, for the) eat off the young undeveloped leaves and 

 destroy thi growing shoot. 



The I aunon try throcephalus, Q\i\.) damaged 



young maize plants by boring into the baseol the leaves, and 



jrega - I e in aumbi 1 5. Thi se insects breed on 



the plants, the parent female often being found 1 ling 1 



a batch of ten to fifteen eggs, or a familj ol young. 



Thi larvae of at least two moths were found on leaves 



of corn, but not in abunda 01 doing much damage. The 



cati cpillars ol two moths ..t the familj Lymantriidae attacked 

 the silks, eating them away flush with the tip of the husk. 

 If this happened before pollination took place the ear could 

 not develop. 



The pests which attack the stem and the ear of the 

 are more numerous and more important. There are th 

 species of moth, the larvae oi which are borers in the steins 

 and ears. These ire Sew ' calamistis, limp., Eldana 

 saccharina, Walk., and Busseola f'usca, limp. The effect 

 produced by these borers varied with the age of the plant. 

 Young plants withered and sometimes died; older p] 

 survived, but showed the effectsof the attack by their stu 1 1 

 growth and withered appearance, and by the Failure of the 

 ears to develop properly. 



When plant- bearing are attacked, these seem to 



be preferred to the stem, but the method of attack varies 

 with each insect. The larva- - Si nuia usually feed in the 

 cob, not as a rule touching the kernels of grain. The larvae 

 of Eldana, on the other hand, prefer the kernel-, through which 

 they tunnel in all direction-, pupating when full grown in 



a white silken coi n, either among the kernels or in the 



husk. 



The two common species, Sesamia and Eldana. are 

 larasitized by a Tachinid tly. which in its turn i- attacked by 

 hymenopterous parasite. 



The larvae of these two species have been found ill 

 stalks of Com plants that have been left standing after the 



have been removed, these stalks thus providing g 1 breeding 



s for the pest. The larvae of Sesamia and Kladana have 



[so been found breeding in the stems ol a car- gi ;--, 

 which is abund nit in the [badan district. 



Another caterpillar^ a bright pink larva of a Noctuid 

 moth, feeds on the silk of the ear inside the husk. When 



ii - attack occurs before the grains are fertilized the 

 ear, of course, does not develop; but when, as often happens, 

 the injury takes place after pollination, no serious harm is 



done. 



Toward the end of the maize season another caterpillar 



test, the larvae of the Pyralid moth (Mussidia nigrivenella, 



Hag.), was found in the almost ripe ears. This is important 



since this insect is one oi the chief pests attacking stored 

 grain, {he firsl infection taking place in the field, and subse- 

 pi. nt generations developing in the -tore. 



The experiments as to the control of the borers in corn 



given results which indicate that the burial of all stalks 



and other corn refuse immediately after gathering the e irs is 



quite satisfactory. The formation of a compost heap of the 



is equallj effective. 



The pests which attack stored grain arc of much the 



same kind as ii other parts of the world, and indeed many -if 



species ire the same: Calandra oryzae, Tribolium 



futum, TenelnrioiAex mauritanicm, and anothei -mall brown 



