The control methods used to protect new-crop groundnuts stored in Kano against insect attack are described.The main method used was the spraying of aqueous suspensions of DDT directly on to the sacking of piles stored in the open and on the walls of warehouses before the nuts were stacked. The solutions were applied with a slow-moving orchard power sprayer, and 50 per cent, wettable powder applied at the rate of 360 mg./sq. ft. was found satisfactory. The BHC wettable powder applied at about 12 mg./sq. ft. was cheaper and equally as good and has now been found safe. Treatment markedly reduced the Tribolium population but had little effect on Trogoderma. Sprays of oil solutions were little used and were not very satisfactory.

DiscussionThe primary object of this investigation was to check that fluorescent lighting is a suitable means of illuminating a chick laboratory where assays for vitamin D, are in progress. I t was satisfactorily established that such lighting, when screened with 26-02. clear glass, did not interfere with the development of rickets in chicks, but the experiments indicated that fluorescent lighting can have a depressing effect on chick growth. When given a rachitogenic diet, birds exposed to IOU ft.-candles of light from a fluorescent tube grew significantly less well than the controls in tungsten light, but such growth depression was not observed at intensities of about 30 ft.-candles. Growth of normal chicks was also depressed in high-intensity fluorescent light, although this depression was not statistically significant.It is possible that this effect was exerted not on the chicks themselves, but on some lightlabile component(s) of the diet. During the first experiment solutions of riboflavin were placed on the brooders at the same level as the diets. As would be expected, the solutions were very considerably reduced in potency after a few days, but the destruction of riboflavin was no greater in the fluorescent than in the tungsten light. Furthermore, the diets were replenished every few days to minimize their exposure to radiation and, although it is conceivable that light-labile factors other than riboflavin might have undergone greater destruction in the fluorescent light, none of the birds showed the slightest sign of any known vitamin deficiexy apart from the intentional production of rickets.

It was desired to ascertain to what extent measurement of the frass produced in groundnuts infested with Trogoderma gvanarzum Everts could be used to assess total damage. A laboratory storage experiment is described in which the dry weight of frass produced is' shown to be approximately equal to the loss of dry matter. Loss of edible nut is thus shown to be about equal to twice the frass weight.

Sacks of decorticated groundnuts stored in two types of open‐air stacks in Kano, Northern Nigeria, were fumigated with methyl bromide under gas‐proof sheets to control Trogoderma granarium Everts. The distribution of the gas during fumigation was investigated.

Many thousands of tons of bagged, decorticated groundnuts are stored for periods of up to 15 months in warehouses in Kano, Northern Nigeria. A large indigenous population of Tribolium castaneum (Hbst.) infests the stored nuts and considerable losses are caused. In 1948, investigations into the control of this and other pests by means of insecticides were commenced. As a result of these trials (Howe, Hayward & Cotterell, 1952) a routine programme of control measures was evolved, based upon the application of y BHC as a water-dispersible powder at monthly intervals. Subsequent observations indicated that large numbers of T. castaneum were present within two weeks after spraying and preliminary experiments suggested that the probable cause was the inadequate persistence of BHC under the climatic conditions prevalent in Northern Nigeria.Eecent intensification of the control measures necessitated a more accurate knowledge of the persistence and toxicity of y BHC at different rates of application under conditions in Kano. Experimental Techniques. General methods.In the preliminary trials, circular discs of sacking were pinned to the surfaces of stacks of bagged groundnuts in a warehouse. A 25 per cent, water-dispersible lindane formulation was applied uniformly over the stack by means of a pressureretaining knapsack-type sprayer. Despite careful application under still conditions the deposits obtained varied from 20 to 47 mg. y BHC per sq. ft.An attempt was then made on a laboratory scale to obtain more uniform deposits by means of a small hand atomiser of the scent-spray type operated by depressing a small plunger. A constant volume of a suspension of 50 per cent, lindane dispersible powder in water was applied to filter papers, but the rate of settling of the suspension resulted in widely varying initial deposits.Eventually it was found that consistent initial deposits could be obtained on filter papers by applying the y BHC in a volatile organic solvent by means of the hand atomiser. This was designed to deliver a constant volume, the rate of application being controlled by varying the strength of the solution. Even, using this technique only a proportion of the actual volume delivered was obtained as a recoverable deposit on the filter papers. With carefully controlled conditions, however, this proportion was sufficiently constant to enable up to a hundred papers to be treated with little variation of initial deposit using the same dosage rate. This may be termed the spraying factor for the particular set of conditions and the accurate knowledge of this factor enabled the following technique to be adopted in all the experiments.A specimen of lindane of melting-point range 109-5-113°C. was prepared by recrystallisation in petroleum ether solution from a 50 per cent, formulation. Initial deposits of approximately 10, 20 and 40 mg. of lindane per sq. ft. were