Field experiments conducted on cotton in southern Sri Lanka, where the main pests were Heliothis armigera (Hb.), Earias vittella (F.) and Pectinophora gossypiella (Saund.), indicated that a damage action threshold of five squares and six bolls per 30 plants could be used for forecasting and early warning in pest management. A parallel sampling study indicated that a sample size of 30 plants would reduce the sampling error to acceptable levels as well as being a more convenient number in the field. An expression that corrects experimentally established thresholds for changes in the cost of control and the market price of the yield is given.

Wild adults of Glossina morsitans morsitans Westw. and G. pallidipes Aust. were caught in a trap baited with carbon dioxide and acetone near Chimotsi Dam in the Zambezi Valley, Zimbabwe. The design of the trap was such that flies were induced to move into a sterilising chamber, where they were treated with a spray of the chemosterilant metepa, after which they were automatically released back into the environment. Exposure to a spray of 0·2 s duration produced between 94 and 100% sterility, with very low mortality. The sterilising unit, its action and performance are described.

In the field in eastern Australia, adult females of Chortoicetes terminifera (Wlk.) underwent stages of body growth, fat accumulation and then egg maturation. Rainfall, and the resulting condition of the feed, determined the speed of development through the stages. If feed was dry, development was slow and stages could be suppressed; but even with feed that was only ‘dry-green’ locusts grew normally, accumulated fat, and then matured eggs after migration. If lush green pasture occurred following rain on the adults, they persisted and soon began to mature eggs. Thus females oviposit in the area where they hatched only if pastures there are lush green, thus ensuring some food for their offspring.

External sexual characters are described for the larvae of Spodoptera littoralis (Boisd) and S. exempta (Wlk.). The characters on the female consist of two pairs of pits on the ventral surface of the eighth and ninth abdominal segments. These pits are visible under a light microscope and can therefore be used for the accurate sexing of live larvae from the third instar onwards. The first- and second-instar larvae of both species could not be sexed using external characters because of their small size. In the males of both species, there are no obvious external sexual characters until the last instar, and therefore the sexes are most easily separated by the presence or absence of the female characters. Third- to sixth-instar larvae of both species were examined for the presence or absence of the female pits and were then sexed by dissection. The accuracy of sexing using the external characters was 90–98% for S. littoralis and 100% in all cases for S. exempta. The histology of the female pits and their appearance under the scanning electron microscope is described. These pits in the female larvae give rise to the external openings of the adult reproductive system.

Diapause induction in Heliothis armigera (Hb.) from the Sudan Gezira was investigated under controlled conditions. A maximum incidence of diapause occurred in response to exposure to low temperature (22°C) and short daylength (12 h) during the larval stage. However, the prepupal and early pupal stages were also sensitive to temperature; if they were exposed to 26°C, diapause was averted. After more than two months at low temperature, some pupae remained in diapause for more than two months after transfer to high temperature (34°C) and only commenced developing when the temperature was lowered again. This may provide a mechanism to bridge the hot dry season and to synchronise emergence with the start of the rainy season. A high incidence of diapause in H. fletcheri (Hardwick) was observed to occur at the end of the rainy season under ambient conditions in the Sudan. Emergence from these diapause pupae occurred in the following rainy season. The different phenologies of diapause in the two species are discussed in relation to their distribution in rain-fed and irrigated vegetation in the Sudan.

In field studies on Glossina morsitans morsitans Westw. and G. pallidipes Aust. in Zimbabwe, various traps baited with attractive odour were used to study the behaviour of flies in each of several stages of response to traps, from the stage of being several metres from the trap to the stage of being retained in a cage on the trap. The numbers of flies that were caught by electrocution, or were observed, as they moved forwards through the stages of trapping were compared with the numbers caught or observed moving in a reverse direction. A variety of stimuli and modifications were investigated for their effects on these movements, leading to provisional recommendations for improving the speed and efficiency of trapping. The most important recommendations were: the outside of trap should be white, with black near the basal entrances, the entrances should be provided with tunnels projecting into trap, and the inside of trap should be made white at base and black at top. The top of the trap should be an open-ended tube around the cone of netting that leads to the retaining cage. Data for Stomoxyinae, non-biting Muscidae and Tabanidae are also presented.

The productivity of adults of Trogoderma granarium Everts was reduced following fumigation of the larvae with high dosages of carbon tetrachloride, ethylene dibromide or phosphine. Carbon dioxide, ethylene oxide, methyl bromide, methyl iodide and trichloroethylene had little influence on the productivity. From 0 to 23 % of surviving larvae diapaused compared with 3 % of untreated ones.

Observations were made over a two-year period on the growth and natural enemies of Lantana tiliaefolia and L. glutinosa growing naturally at nine sites covering different climatic areas of Paraná State, south Brazil. Lantana was found to be subjected to continuous attack by insects and/or fungi throughout the year, with different species causing damage at different times. Temperate-climate sites had a more diverse complex of insects and a greater intensity of attack than warmer-climate sites. Shrubs in sites which suffered severe insect attack, especially during the previous season, flowered and fruited significantly less than those which had suffered only light attack. Differential weighting of the principal phytophagous insects demonstrated that feeding by insects of some groups may be more damaging than that by others. The relevance of the results to the search for biological agents for control of lantana in Australia is discussed.

Locomotor activity in an actograph and oriented locomotor movements in an olfactometer were recorded for fifth-instar nymphs of Rhodnius prolixus Stål exposed to test stimuli expected to elicit food-seeking behaviour. A natural food source (hamster or human forearm) proved to be the most attractive stimulus. Warmth alone was least stimulating for long-range orientation. As with mosquitoes, carbondioxide and moisture proved to be attractive, as well as the odour of a hamster. Lactic acid did not seem to play an important role in orientation. Activation by the different stimuli was most pronounced during the scotophase of the circadian cycle. Circadian activity ran-free for two weeks in constant darkness. The results indicate that the stimuli that elicit locomotor activity in the actograph are in some way implicated in the switching of the taxis mechanisms that utilise the airstream for orientation.

The growth of populations of Triatoma infestans (Klug) depends on temperature and blood-intake. Experiments are described which demonstrated the density-dependent relationship between population size, blood intake and population growth at different temperatures. The number of bugs feeding and their mean blood intake was lower at high bug densities than at low ones, both with restrained chickens and with unrestrained mice as hosts. When blood intake was restricted, the development times of all nymphal stages were increased, and female fecundity was decreased. Previous work showed also that reduced blood intake led to an increased tendency for adult flight. It is thought that at high bug density the three factors, increased development times, decreased fecundity and increased flight, operate to restore the population to a stable density without promoting an increase in mortality. The mechanism linking population density to nutritional status seemed to depend on host irritability, which interrupted the bugs' feeding. Bugs which passed a certain threshold meal size would not resume feeding if interrupted, even though their blood intake was well below normal. The difference between the minimal threshold meal and a normal meal is thought to provide the nutritional elasticity within which the development processes are regulated. It is suggested that this mechanism is characteristic of K-strategists, whereas r–strategists such as mosquitoes tend to continue attacking, even if interrupted, until they achieve a normal meal.

Survival and wood consumption were measured for laboratory groups of Porotermes adamsoni (Frogg.) maintained over a range of constant temperatures from 8 to 29°C. The termites were fed on sound blocks of Pinus radiata, Eucalyptus regnans, decayed E. ?viminalis, and outer (sound) and inner (decayed) heartwood of E. pauciflora. Above 21 °C, diet influenced the pattern of survival, wood consumption and wood consumption adjusted for survival, resulting in a significant temperature × timber interaction. In the upper range of the temperatures used, the termites survived in larger numbers or for longer periods on decayed than on sound wood and ate more of it. From the results, it is clear that difficulties arise when employing laboratory data to estimate feeding activity of termite populations in the field. Knowledge of the correlation between the performance of termites in laboratory groups with that of members of a field colony is still sparse.

Based on previous studies of the trap-orientated behaviour of Diptera, a variety of new traps was designed to maximise the speed and probability of capturing Glossina morsitans morsitans Westw. and G. pallidipes Aust. arriving near traps, and to minimise the probability of capturing other flies. In Zimbabwe, catches were made with these traps in the presence and absence of carbon dioxide and acetone as odour attractants, leading to the identification of a simple trap for which the probability of capturing Glossina spp. was up to twice as great as it was for a standard biconi-cal trap, and for which the probability of capturing other Diptera was very much less than it was for the biconical trap. The probability of capture by the simple trap was 100% for G. pallidipes, 51% for G. m. morsitans, 6% for Stomoxyinae and 1% for non-biting Muscidae. Half the tsetse that arrived near the simple trap were captured within 5 min of arrival. The number of tsetse that contacted simple targets designed to expose flies to insecticide amounted to 32–263% of the catches of a biconical trap. The use of traps and targets for tsetse control, and the procedures for trap improvement, are discussed.

Development rates of engorged examples of Ixodes ricinus (L.) and the onset and duration of questing activity of unfed ticks were investigated in gauze cages in the field in the Irish Republic. Development rates of the various stages were broadly similar to those described in other studies but differed in small detail from most of them. It was found that larvae that fed during or after the first two weeks of August entered diapause. The activity periods of questing ticks were found to agree closely with observations made in the field, and the origins of the various peaks in tick activity in the field were thus elucidated. It was established that considerable interchange between autumn-feeding and spring-feeding populations of ticks can occur, and it is concluded that the extent of this is largely controlled by the weather, being accentuated by high summer temperatures.

Coccus celatus De Lotto is now established on coffee in Papua New Guinea where it is causing some concern. As a result of studying extensive collections of this species from the Sudan and Papua New Guinea, it is now possible to synonymise the name C. consimilis De Lotto with C. celatus. An account of the distribution and host range is given.

The identity of Chilo kanra (Fletcher), an obscure stem-borer of the wild and semi-cultivated grasses Saccharum fuscum and S. arundinaceum in northern India, is ratified on the basis of recently collected material from Bihar. A neotype is designated, and the adults and genitalia are illustrated. The species is differentiated from its congener C. partellus (Swinh.), a widely distributed pest of sugar-cane and other graminaceous crops in India and Africa. A neotype is also designated for C. saccharicola Fletcher, a stem-borer described at the same time as C. kanra and now found to be conspecific and a junior synonym.

In a revised classification of the Tropiduchidae, which includes a number of species injurious to crops, the family is divided into 15 tribes, of which six (Cixiopsini, Eporini, Isporisini, Neommatissini, Remosini and Turneriolini) are proposed as new, two (Eutropistini and Tangiini) are given new status and seven are redefined. New subtribes (Clardeina, Neotangiina and Duriina) are erected in Eporini, Tangiini and Eutropistini, respectively, and Kazeruniina is given new status in the last. The genera Chiotasa and Habrotasa are transferred to Achilidae, Dolia, Hiracia, Karna, Parahiracia, Siebererella and Gastrinia to Issidae, and Kruegeria to Ricaniidae, and Dichoneura is brought into Tropiduchidae from Delphacidae. Biruga chariclo Fennah is transferred to Athestia to form a new combination, and Tambinia theivora sp. n. is described from material that included examples collected on tea.

Activity in virgin and pregnant females of Glossina morsitans morsitans Westw. was very low and mostly took the form of short bursts of flight. Recently-fed virgins and females in early and mid-pregnancy were least active. In late pregnancy, activity increased and more walking occurred. In all classes of females, activity was least around midday, but the V-shaped curve became less pronounced as parturition approached. There was evidence of a slight preference for black over white surfaces when landing but a clear preference for black resting sites. Virgin females preferred to alight and rest on vertical surfaces at the borders of areas of visual contrast; pregnant females preferred to alight and rest on horizontal surfaces and showed no attraction to regions of contrast. In a horizontal light gradient, pregnant females selected lighter resting sites as the day progressed. In late pregnancy, there was an increasing tendency to rest in darker sites. Increasing the temperature in the light gradient caused an increase in activity around 34°C and a switch to photonegative behaviour. After larviposition, the females became strongly photopositive even at high temperature (38°C), but after a feed they reverted to the ‘normal’ photonegative response to high temperature.

The recent attack by Pulvinaria iceryi (Sign.) on sugar-cane in Mauritius is discussed in the context of other attacks by sap-sucking Hemiptera in the Mascarenes. P. iceryi is compared with its allies P. elongata Newst., P. saccharia DeLotto, P. sorghicola De Lotto and P. tenuivalvata (Newst.). The name of P. longisqua De Lotto is sunk as a synonym of P. elongata and a key is presented for the five related species.

Age-specific life-table data were collected over a year for field and insectary populations of Phoracantha semipunctata (F.) on logs of Eucalyptus grandis in Malawi. Most mortality occurred in the larval stage, and the major mortality factor was intraspecific competition. Severe overcrowding led to a reduction in population density from one generation to the next. Overcrowding also led to a reduction in beetle size and to a shift in the sex ratio in favour of males. Elimination of potential breeding sites is recommended as an effective control measure for this pest.

After checking the identity of numerous mealybugs of the genus Planococcus from the south Pacific, many of which were previously recorded as P. citri (Risso), it was established that the most widespread is the recently described species P. pacificus Cox. P. citri is present in some islands, but the collection dates are recent, suggesting a recent introduction. Although P. pacificus is known from the area since the first quarter of the present century, it may have been introduced also. P. lilacinus (Ckll.) possibly arrived from southern Asia and P. dioscoreae Williams from the eastern part of the Oriental Region. The known host-plants are listed.