In 1927, 1931 and 1935, the writer published three papers on the food-plants of Nigerian insects in this Bulletin (18, pt. 1 ; 22, pt. 2 ; and 26, pt. 2). The present paper contains additional data obtained between November, 1934, and March, 1936. On the advice of the Botanical Section, Nigerian Agricultural Department, certain changes have been made in the nomenclature of economic plants. In the previous papers the nomenclature employed in the Kew Bulletin entitled “ The Useful Plants of Nigeria ” was adopted. The following list shows the English or native name of the crop and the old and new scientific names.

Ketumala thea sp. n. is described from tea and the shade trees Erythrina lithosperma and Glirididia sepium in South India. Descriptions are also given of K. singapurana sp. n. and K. nigropunctata (Distant) comb. n.

In both a susceptible and a diazinon-resistant strain of house-flies (Musca domestica L.), adults of both sexes were most susceptible to diazinon immediately after they had emerged from the pupae. Their resistance increased for two days after emergence and remained steady for the next three days, and the increase was proportionately larger in the resistant strain. Taking flies 2 ± 2 hr. old as a basis, the increases in resistance by the third day were 1−2½ and 3½−6½ times for susceptible and resistant males, respectively, and 2−5½ and 9−18½ for susceptible and resistant females. In both strains, the two sexes were equally susceptible to diazinon during the first day, but later the females were more resistant than the males. The resistance factor (ratio of LD50's of resistant and susceptible strains) was least immediately after emergence and increased with age; it was 15–30 in flies 2 ± 2 hr. old and 50–90 three days later. There was no direct relation between changes in resistance and changes in the weight of the flies on aging. The resistance factor to diazinon should be measured not earlier than three days after emergence to obtain reproducible values. Removal of the ovaries in flies less than one day old did not affect the increase in resistance with age.

Tetrastichus giffardianus is a gregarious koinobiont endoparasitoid of tephritids, including Ceratitis capitata, which is one of the most important fruit pests worldwide. The objective of this study was to evaluate the effect of constant temperatures on the biology and development of the egg-adult period of T. giffardianus in larvae/pupae of C. capitata to construct a fertility life table. The study was carried out in climatic chambers at constant temperatures of 15, 20, 25, 30, and 35 ± 1°C, 70 ± 10% relative humidity and a photophase of 12 h. Complete egg and larval development occurred only at temperatures of 20, 25, and 30°C. The mean longevity of males and females was inversely proportional to temperature. The time of development of the pre-imaginal period was influenced by temperature and ranged from 41 days at 20°C to 11 days at 25°C. The best T. giffardianus performance occurred at 25°C when the intrinsic rate of increase was 0.21, the mean generation time was 20.43 days, the time required to double the population was 3.33 days, and the finite rate of population increase (λ) was 1.23. The results of this study provided information for the establishment of mass rearing and an evaluation of the adaptability of T. giffardianus to different environments, which is necessary for the use of this parasitoid in the biological control of tephritid pests, particularly C. capitata.

The consumption rate, survival, and developmental duration of the coccidophagous coccinellid Rhyzobius lophanthae (Blaisdell) (Coleoptera: Coccinellidae), a predator of the armored scale insect, Aspidiotus nerii Bouche (Hemiptera: Diaspididae) were studied under laboratory conditions at two temperature regimes of 25 ± 1 and 30 ± 1°C, 50–65% RH, and 16L:8D. Developmental time (egg to adult) significantly decreased with increase in the temperature. It lasted 27.5 days at 25 ± 1°C and 21.3 days at 30 ± 1°C. The development threshold of R. lophanthae immature stages was 7.823°C, while the thermal constant was 472.379 degree-days. No mortality was recorded during the incubation period. The total mortality rate amongst the larval instars was with 3.33% at 25 ± 1°C and 6.77% at 30 ± 1°C. The sex ratio male to female was 1:1.06. The consumption rate significantly increased with increasing temperatures and within the larval instars. The four larval instar consumed 24.3 and 33.5 adults of A. nerii at 25 ± 1 and 30 ± 1°C, respectively. Overall, micro-climate temperature had a significant impact on the biological parameters of R. lophanthae.

The following notes are based on observations made during the months of June and July, in and near the Songwe valley.

The coffee berry borer, Hypothenemus hampei Ferrari (Coleoptera: Curculionidae, Scolytinae), is the most devastating insect pest of coffee worldwide. It feeds on the beans inside the berries leading to significant crop losses and unmarketable products. This study aims to model the impact of temperature on H. hampei fecundity and population growth parameters, as a contribution to the prediction of infestation risk. The fecundity was assessed on fresh coffee beans at six constant temperatures in the range 15–30°C, with RH 80 ± 5% and photoperiod 12:12 L:D. Nonlinear models were fitted to the relationship between fecundity and temperature using the ILCYM software. The best fecundity model was combined to development models obtained for immature stages in a previous study in order to simulate life table parameters at different constant temperatures. Females of H. hampei successfully oviposited in the temperature range 15–30°C, with the highest fecundity observed at 23°C (106.1 offspring per female). Polynomial function 8 model was the best fitted to the relationship between fecundity and temperature. With this model, the highest fecundity was estimated at 23°C, with 110 eggs per female. The simulated net reproductive rate (R0) was maximal at 24°C, with 50.08 daughters per female, while the intrinsic rate of increase (rm) was the highest at 26°C, with a value of 0.069. Our results will help understand H. hampei population dynamics and develop an ecologically sound management strategy based on a better assessment of infestation risk.

The northern house mosquito (Culex pipiens pipiens L.) is a vector of several important pathogens and comprises two epidemiologically distinct ecotypes (molestus Forskål and pipiens). The delimitation of its ecotypes is a crucial, yet controversial step in vector surveillance due to varying diagnostic values of different characters. Therefore, we reviewed the success of a diagnostic assay based on the mitochondrial cytochrome c oxidase subunit I locus (COI) by analyzing previously published sequences of molestus and pipiens sampled in different geographical areas. Next, by genotyping individuals from Northern Serbia at this locus, we additionally assessed whether genetic structure of urban and rural Cx. p. pipiens ecotypes corresponded to the admixture pattern. Finally, to account for the different susceptibility of genetic markers to introgression, we also analyzed genetic structuring based on the ribosomal internal transcribed spacer 2 (ITS2). No latitude-dependent differentiation of Cx. p. pipiens ecotypes was found at a global level, with the COI assay further failing to accurately identify molestus and pipiens ecotypes. Likewise, both individual- (BAPS) and population-based (analysis of molecular variance and FST estimates) methods showed no significant urban/rural genetic differentiation in Serbia, indicating unhindered gene flow between different Cx. p. pipiens habitat types. The findings challenge the previous instances of Cx. p. pipiens ecotype identification, while also spotlighting the vectorial capacity of their hybrid offspring.

Insecticide application and augmentative parasitoid releases are often considered incompatible. However, pesticide applications and parasitoid releases can be integrated into a pest management scheme if there is careful time scheduling of these interventions. In this study, we assessed the influence of commonly used insecticides (chlorpyrifos-methyl, deltamethrin, pyriproxyfen, thiamethoxam) in olive agroecosystems to two currently present Trichogramma parasitoids in the Mediterranean basin. Exposure to insecticides in relation to parasitoid's development was also tested. Both, insecticide type and application time influenced parasitism and the emergence rates of the two parasitoid species. Chlorpyrifos-methyl had the strongest impact on parasitoids resulting in low numbers of emerged adults followed by deltamethrin. The two parasitoids also exhibited different levels of susceptibility to the insecticides used. Potential integration of insecticides to integrated pest management using Trichogramma parasitoids is discussed.

The writer of the following notes has been engaged on entomological investigations in Fiji, Australia and Hawaii since 1914; the work has been entirely confined to the pests of sugar-cane and has been carried on mainly in the first-mentioned country, where insect depredations are very serious and materially reduce the profits on a considerable number of plantations. The investigation of these Fijian cane pests open up a field that is practically new, and so the work will probably continue for some considerable time. The length of the period that is likely to elapse before the publication of final results is such that it seems desirable to place on record a few of the main points in the life-histories of the more important insects of the sugar-cane plantations of that country, and so the writer has complied these notes containing summaries of their life-histories in so far as they are at present known to him.

Experiments were carried out to study the possibilities of using ground or crop interference with the spray laden slip-stream of a helicopter flying slowly in the ground cushion to obtain a high dynamic catch of spray droplets. Experiments were carried out in 1945 and 1946 with a Sikorski type Y.R.4.B. helicopter and experimental spraying gear designed for the purpose.

The forward portion of the slip-stream annulus was explored by means of spraybars placed in three different positions. The position in the sector between angles of 15° and 45° with the direction of forward flying was found to give the best all-round cover and was the position in which the spray deposit was less influenced by alterations in the control-surfaces of the helicopter.

To obtain a fairly wide swathe of approximately 70 ft., the equivalent of two rotor diameters, the forward speed of 6–8 m.p.h. was found to be optimal, and it was observed that not only was good cover of the upper surfaces of the leaves obtained but the spray-laden slip-stream also gave a good cover of the vertical surfaces of the plants outside the rotary periphery and, in certain boom positions, descended and in rebounding produced a cover of the lower surfaces.

In order to obtain maximum dynamic catch and a good cover of the lower surfaces of leaves, spray-bars must not be more than 6 ft. above ground.

Helicopter spraying is wind dependent and in wind velocities above 12 m.p.h. uniform cover of spray deposit does not appear to be feasible.

The performance of the flattened out slip-stream and rebound depends on the type of crop, and as this affects the dynamic catch to a considerable degree, this phenomenon will be the subject of a special investigation.

The forward portion of the slip-stream was found to give a more even spray deposit than the aft portion because in the latter case vortices are caused by the rotor blades which affect the spray deposit.

In view of its limitations as regards speed and dependence on wind velocity, economic application of spray chemicals by helicopter at a degree of efficiency and workmanship equal to that of ground machines is only possible with a heavy load-carrying helicopter. A specification for such a machine has been issued to the manufacturers of rotory wing aircraft.

It is hoped that this report will be followed by a report on the performance data of the new spraying apparatus designed for the Sikorski S.51 which is based on the results of these investigations.

The importance of finding the effect of defoliation on the reproductive capacity of Cordia macrostachya is explained in view of the proposed introduction of two species of leaf-eating beetles from Trinidad into Mauritius for the control of this weed.

An account is given of experiments in which the production of inflorescences and fruits was compared in defoliated and control plants.

The results show that defoliation has a significant effect in reducing the reproductive capacity of the plant.

The galls induced on Tamarix spp. in Pakistan by six species of Psectrosema are described, and the known host ranges and geographical distributions of these species are given, together with information on seasonal biology and adult behaviour based on field surveys and laboratory observations. Parasitic Hymenoptera and other insects associated with the galls are listed.

Both Culex decens and Culex invidiosus are widely distributed in British West Africa. In the Gold Coast both have been taken in all the three divisions into which the country is divided, namely, the Colony proper, Ashanti and the Northern Territories; the records at Accra showing the following distribution: —

Experiments were carried out to determine whether Oryzaephilus surinamensis (L.) was attracted to water on a wick suspended in an arena. When insects were preconditioned at 25, 50, 75 or 100% RH, they were attracted to the water source. Those preconditioned at 50% RH gave the greatest response and those preconditioned at 100% RH, the least. Measurement of the humidity changes in the arena caused by adding a wick containing 5 Μ1 of water showed that the gradient between the edge and centre was steepest at the start of an experiment when insect activity was also greatest. About 30 min after a wick had been placed in the arena, virtually all the water (about 94%) had evaporated, the humidity had equalised over the arena and the insects were no longer attracted to the wick. This behavioural response is discussed in relation to the insects' environment.

The object of the present paper is to place on record a number of observations made by the writer in the Ibadan district of Southern Nigeria in the years 1922 to 1925, in the hope that they may be of some interest to other workers in Africa.

The writer wishes to acknowledge his indebtedness to Dr. G. A. K. Marshall and the specialists of the Department of Entomology in the British Museum for identifying the insects mentioned, and to Dr. A. W. Hill, Director of the Royal Botanic Gardens, for determining the majority of the plants.

Following the discovery of Lydella jaliscosp. n. (from Jalisco, Mexico), a parasite of the Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Pyralidae), the limits of the genus Lydella Robineau-Desvoidy have been widened to include Diatraeophaga Townsend syn. n., Metoposisyrops Townsend syn. n., and Metagonistylum Townsend syn. n. All species regarded as belonging to Lydella are listed, with L. minense (Townsend) comb. n., L. oryzae (Townsend) comb. n., L. scirpophagae (Chao & Shi) comb. n., L. sesamiae (Mesnil) comb. n., and L. striatalis (Townsend) comb. n.

Several species of Dynastid beetles are serious pests of yam (Dioscorea) in Nigeria, the adults attacking the setts and new tubers underground. The base of the yam vine and the roots are not generally damaged. The most important species is Heteroligus meles (Billb.).

H. meles does not breed in the yam fields, and the adults fly to them from breeding grounds that are distinct, and to which they return later.

The cultivation and growth of the yam plant in Nigeria are briefly described. Small tubers, or cut pieces of tubers (setts) are planted. The earlier the date of planting and of emergence of the vine from the soil, the heavier the vine and the new tuber.

An account is given of observations on the infestation, in relation to crop growth, of a plot of yellow yams (D. cayenensis) planted near Benin, in Western Nigeria on 29th March 1958.

Adults of H. meles were taken, from 3rd April to 26th June and again from 8th to 21st November, between 7 and 9 p.m., at a light-trap placed at a distance of ¼ mile from the plot.

Beetles entered the soil of yam hills within six inches of the vine, usually before 7 a.m., on mornings following evening flights, the entry holes usually being identifiable. The first vines were seen in the experimental plot on 19th April. Beetles did not enter a yam hill unless the vine had emerged.

The longer the exposure to flying beetles, the more likely were plants to be attacked, and bigger vines attracted more beetles than did smaller ones. Later planting decreased beetle damage, but a lower yield resulted.

At first the beetles fed on the sett, making and increasing the size of fewer lesions than later on the new yam. About the time that the flying period ended, the setts were starting to rot, and the beetles left the immediate vicinity of the yam plant, as no acceptable food was available. Most moved deeper into the soil, but a few left the plant altogether and flew away. After the new tubers had begun to develop, the beetles returned in early August from their positions deeper in the soil to feed on them, constantly making new lesions, more numerous but smaller than those made in the setts, averaging about 4 g. of yam eaten.

During late August and again in late September, a few beetles moved underground from the original plants attacked to others. In mid-November, the beetles left the yam fields altogether, presumably returning to the breeding area.

The reasons why the beetles fly away from the yam fields remain uncertain, but they may include the seasonal decline in rainfall, the maturation of the yam tuber and the development of the gonads.

Factors that can affect the rate of attack are the dates of planting and harvesting in relation to the period during which the beetles fly, the method of cultivation and the variety of yam planted.

The black-headed palm caterpillar (Nephantis serinopa, Meyr.) has been known to be a serious pest of coconut palms both in Ceylon and South India for many years past, and during the past ten years its appearance on a serious scale along the Malabar coast in South India has been attracting the attention of the Entomological Section of the Madras Agricultural Department. Among the different methods of control, the utilisation of the natural enemies of the pest has been tried to some extent. One of the more important natural enemies found to exert some appreciable influence on this pest was a Eulophid wasp, Trichospilus pupivora, Ferr. As one of the officers of the Entomological Section engaged in the work connected with this coconut pest, the author had opportunities of closely studying this parasite, and in this paper a brief account is attempted of the bionomics of this insect and of some methods employed in breeding it on a large scale.