1. Collections of Cydia pomonella were made in France in 1928 and 1929–30.

2. The numbers of moths and parasites that emerged from the collections are given.

3. The biology and host-lists of the parasites are dealt with, and information on the larval anatomy is given.

4. Low percentages of parasitism of the larvae were found, and it is concluded that predacious birds, and the removal of larvae with the crop, must be important factors in the control of the Codling Moth in France.

Several aspects of the biology of the tomato moth, Lacanobia oleracea (Linnaeus) were investigated when these insects were fed an artificial diet and kept under laboratory conditions. The six larval stadia occupied a total period of 35.6 days at 20°C and 65% r.h. Larvae of each stadium could be separated by their head capsule widths, but not weight ranges, which overlapped. Feeding studies carried out on larval L. oleracea revealed instar dependent changes in the indices of food consumption and utilization. Larvae increased in weight from the fourth to sixth instar due to a combination of the increased efficiency with which ingested food was converted to body tissue, and increased food consumption by older larvae. Sixth (final) instar larvae exhibited three distinct behavioural phases; during one of these, the feeding phase, larvae consumed a greater amount of diet than either the fourth or fifth instars. The mean pupal period of non-diapausing pupae was 25 days. Pupal diapause was induced when larvae were reared under short day conditions. The male to female sex ratio of adult moths was 1:1.3. Mating generally began during the first scotophase after adult eclosion, and stopped soon after the start of the next photophase. Females usually mated only once, but males were capable of mating at least seven times. Oviposition normally commenced on day 2 of adult life, and the mean total egg production was 1186 eggs/female. Sex pheromone components were not present in solvent extracts of the pheromone glands of 20-day-old female pupae, but low levels were detected in pharate adults. A further increase in pheromone levels in newly-emerged moths was detected and, in isolated virgin moths, pheromone levels increased each day of adult life until day 9. Pheromone levels were significantly lower in two-day-old mated adult females, than in two-day-old virgins.

There are three moth-borers of sugar-cane in Mauritius, Proceras sacchariphagus Boj. (Crambid.), Sesamia vuteria (Stoll) (Agrotid.) and Olethreutes schistaceana (Snell.) (Olethreutid.).

The eggs of all three are parasitised by Trichogramma sp. ? australicum Gir., while a second undetermined species of Trichogramma parasitises the eggs of Sesamia and Olethreutes. Sesamia eggs are also parasitised by a Scelionid, Platytelenomus sp. ? hylas Nixon.

The impact of Phenacoccus manihoti Matile-Ferrero on growth and tuber yield of cassava, and the results of its biological control by the exotic parasitoid Epidinocarsis lopezi (De Santis) were investigated in a survey of 60 farmers' fields in Ghana and Ivory Coast over an area of 180 000 km2 of the savana and forest ecosystems. Twenty-nine variables associated with plant growth, agronomic and environmental factors, and insect populations were recorded. Densities of P. manihoti were closely correlated with stunting of the cassava shoot tips and, less so, with the rate of stunting early in the growing season. With increasing mealybug infestations, average harvest indices declined and populations of E. lopezi and of indigenous coccinellids increased, but parasitoids were found at lower host levels than were predators. The length of time E. lopezi had been present in an area was the most important factor influencing mealybug densities. Thus, P. manihoti populations were significantly lower where E. lopezi had been present for more than half the planting season than in areas where E. lopezi was lacking or had been only recently introduced. A significant proportion of the farmers in the savanna zone, where P. manihoti populations were much higher than in the forest zone, had observed this decline due to E. lopezi. Tuber yield losses due to P. manihoti in the absence of E. lopezi were tentatively estimated at 463 g/plant in the savanna zone. No significant effect was found in the forest region. When E. lopezi was present, average P. manihoti damage scores were reduced significantly, both in the savanna and forest regions. The increase in yields was 228g/plant or about 2.48 t/ha in the savanna region.

Females of Anopheles darlingi Root were the commonest (98·6%) of 5464 anophelines taken in 866 man-hours of human bait catches at night, in or near houses in the rain forest in Suriname during 1979–81, but their abundance could not be related to the prevalence of human malaria. In most endemic areas, few females were taken. At Aseli Kamp (4°17'N, 53°24'W) on the Lawa River, biting females were most abundant from April to June, during the long rainy season and rare or absent from September to March, during the long dry, short rainy and short dry seasons. At Apoma Tapoe, however, only 40 km downstream, they were most abundant in october and November, during the long dry season. Females entered houses to feed, with peak biting activity between 22·00 and 23·00 h, and were observed to rest near the collector for a mean of 7·7 min before and 17·1 min after feeding. No females were found resting by day, in buildings or out of doors. The mean parous rate of 827 females from biting catches was 43·6%. The expected biting rate of females was reduced by 20·3% in a house for six nights after it had been sprayed with DDT wettable powder (2 g/m2 active ingredient), and by a mean of 82·6% during seven nights in a camp where the edge of the surrounding forest was sprayed with an ultra-low-volume mist of 95% fenitrothion (1·3 ml active ingredient per metre of perimeter) on the first, third and sixth days. A. darlingi larvae were found at Aseli Kamp in all seasons along the river's edge between water hyacinth plants (Eichhornia) and floating debris, and during the long rains in flooded forest.

A self-supporting colony of Glossina morsitans morsitans Westw. fed through Agar/Parafilm membranes upon haemolysed bovine blood for five days and upon the ears of living rabbits for one day each week (M5R1) is reported. This colony produced offspring intermediate in weight between those produced by adults fed exclusively upon living hosts (R6) and those fed exclusively through membranes (M6). Life span and fecundity of M5R1 adult females was close to that of R6 females and superior to that of M6 females whose reproductive performance was inadequate to maintain a colony. The different regimes did not affect feeding frequency, although adult nutrient intake was lower in M6 than in R6 females, and M5R1 females were intermediate. Larval growth as measured by dry weight increase and total nitrogen content at 24-h intervals throughout the second reproductive cycle showed that growth rates of all three instars were lower with M6 than with R6 feeding regimes, while the M5R1 regime produced an intermediate effect. There was a linear relationship between dry weight and total nitrogen content for all developmental stages from egg to fully grown third-instar larva, and this was unaltered by the feeding regime, suggesting that gross nutrient composition remained constant and was unaffected by the adult diet. Evidence is presented that a large critical blood-meal ingested on or about the fifth day of a nine-day interlarval period provides the bulk of nutrient for larval growth. Histological examination of the adult uterine glands showed that the greatest secretory activity was coincident with a waning of cell size and that nutrient secretion is a continuous process from the time of hatching of the first-instar larva until parturition. It is concluded that poor reproductive performance of adults maintained on in vitro feeding regimes is due mainly to quantitative aspects of feeding rather than qualitative deficiencies in the diet.

Details are given of a trap for Phlebotomine sandflies attracted to a small mammal placed in a cage incorporated in the trap. It was developed in British Honduras for the purpose of studying the sandflies attracted to proven or possible hosts of Leishmania, other than man. The results of initial tests carried out at Central Farm from November 1964 to February 1965 are reported. These provided evidence that the sandflies caught in the trap were attracted to the rodents used as bait, and did not enter by chance; unbaited traps caught virtually no flies. In traps baited with rodents known to be reservoir-hosts of Leishmania, the species caught in greatest numbers was Phlebotomus apicalis Floch & Abonnenc, and amongst those caught in smaller numbers were P. cruciatus Coq. (including P. diabolicus Hall) and P. deleoni Fairchild & Hertig; it is suggested that all three are possible vectors of leishmaniasis in British Honduras. The relative numbers of the sandfly species caught in the traps were very different from those caught on man in British Honduras and by direct catching on animals in Panama.

Based on data collected during regular, biconical trap sampling of Glossina palpalis palpalis (R.-D.) over two and a half years during and after two insecticide programmes in Ivory Coast, various analytical techniques were developed which allow the estimation of mortality rates and life-time fertility from ovarian age distributions of female flies. Data from trapping-out experiments were used to calculate the natural resilience of local populations. The results reveal that the dynamics of the populations showed considerable local variation, with two major types of sites. At those sites with large numbers of domestic pigs, the fly population was dense and showed a high degree of natural resilience and a low mean mortality rate, so that it could be selfsustaining through reproduction alone. At sites with few pigs, the fly population was scarce and showed a lower degree of natural resilience and a higher mean mortality rate such that the population could only be maintained by continuous input of immigrant flies. Studies of the natural dynamics of tsetse can be used to predict the likely effectiveness of alternative control schemes; fly mortality rates must be permanently increased in order to reduce fly numbers or infection rates to below some threshold for disease transmission.

The ecology of the adult mosquitos of the Northern Guinea Savannah was studied from 1960 to 1962 in the Kaduna area mainly in two Hausa villages, Anguwun Rimi and Kangimi, and in nearby Fulani settlements. A description of the area and various types of village huts is given together with an account of the climate and meteorological data. Emphasis was on the Anophelines and their relation to malaria but at the same time information on the Culicines is presented.

Biting catches, in which mosquito scouts acting as human bait collected adults in test-tubes, were performed for over a year in A. Rimi. A total of 38 species was caught in these collections, but many appeared only infrequently. By far the commonest mosquito biting man was Anopheles gambiae Giles which had its peak density towards the end of the rains, in September, and although its population was greatly reduced during the dry season it however remained the principal anthropophilous species. In the area in which the catches were performed A. nili (Theo.) was the second commonest mosquito, and with the exception of March it was more abundant than A. funestus Giles. In other areas it was not so common, and in Kangimi A. funestus was almost as abundant during the rains as A. gambiae, and at the beginning of the dry season it became the main Anopheline. Most of the other Anophelines that were taken at bait were only caught in any numbers during the latter part of the wet season; for the remainder of the year they were virtually absent. Mansonia uniformis (Theo.) was abundant in October, but for the rest of the year it was rarely taken; M. africana (Theo.) was found to be uncommon in the area. Due to the close proximity of Kaduna to A. Rimi, Culex pipiens fatigans Weid., a species now associated with urbanisation and not with villages, was common. Both bait catches and pyrethrum spray-sheet collections in houses showed that it greatly increased in numbers at the beginning of the rains, but that this high level of density was not maintained, and during the greater part of the wet season the species was less common than in the early rains. Aedes aegypti (L.) sens. lat. was rare both in houses and in bait catches; the two principal Aedes species were Ae. vittatus (Big.) and Ae. furcifer (Edw.); the latter species is confined to the Savannah zones. The biting cycles of the three main Anophelines were characterised by maximum feeding occurring after midnight. In both A. gambiae and A. nili there were two main peaks, between 2400 and 0100 and between 0300 and 0400 hr.; in A. funestus, maximum biting occurred between 2400 and 0200 and between 0300 and 0400 hr.

By the use of mosquito nets baited with humans, both inside huts and out of doors, the relative attractiveness, to the anthropophilous Anophelines, of man in the two situations was assessed. It was found that A. nili was equally attracted to man in both situations, and although slightly greater numbers of A. gambiae and A. funestus were found biting out of doors, for practical purposes man is equally attractive in both places. Certain species, notably A. coustani Lav. sens, str. and A. hancocki var. brohieri Edw., were rare or absent in the inside and outside bait-net collections, whereas they were readily taken in both situations in test-tube catches performed in the same locality on the same nights. In fact, more specimens of A. coustani sens. str. were taken in the outside test-tube catches than of either A. funestus or A. nili, and A. hancocki var.brohieri was commoner than A. funestus.

Catches of adults from mud walls and thatch roofing of typical round village huts showed that there was generally no appreciable difference in the attractiveness of these two surfaces to either A. gambiae or A. funestus, but as the thatch only comprised about 34–44 per cent, of the internal surface area of the huts the absolute number resting on the walls will be greater than on the roof.

Spray-sheet collections showed that besides large numbers of A. gambiae and A. funestus resting; during the day-time in normal mud-walled living huts of the Hausa, high densities of these species were found in the Fulani huts, which do not incorporate any mud in their design, and moderate numbers were also caught in Hausa villages in the zaures (huts resembling living ones, but without doors, furniture or fires and not normally slept in at night). Collections from outdoor resting places demonstrated that considerable day-time resting occurred in uninhabited huts, under eaves of huts, both inside and under eaves of goat stables, in kitchens, amongst the tightly woven grass mats termed ‘ zana ’ matting, in rodent holes, tree holes, pots, near wells, amongst grass and vegetation and underneath and under the eaves of grain bins. Surprisingly few examples of A. nili were found in any of the outside resting shelters examined, despite the fact that both exit traps and spray-sheet collections showed that it bit freely in huts but rarely stayed in them. The large number of A. gambiae and A. funestus found out of doors, coupled with the exodus of blood-fed individuals from huts, showed that an appreciable amount of exophily occurred in both species. Entrance traps fitted to village huts caught, in addition to unfed, both blood-fed and gravid (taken to include half-gravid and full-gravid) females of A. gambiae and A. funestus, suggesting that a certain amount of exophagy and re-entry of gravid individuals was occurring. Numerous precipitin tests were made on blood-meals obtained from A. gambiae, A. funestus and A. nili. and a few also from most of the other species. Results showed that the three principal Anophelines were strongly anthropophilous but the exophilous population of A. funestus and A. gambiae showed some deviation to other vertebrates. Most of the other Anophelines, e.g., A. rufipes (Gough) sens, lat.,A. hancocki var. brohieri, A. flavicosta Edw. and A. longipalpis var.domicolus Edw., found resting in goat shelters and other outdoor sites had fed mainly on other vertebrates.

On account of the already available information on the infectivity of both A. gambiae and A. funestus in Northern Nigeria, dissections for estimation of sporozoite rates were only carried out on their exophilous populations, and in both species these were shown to contribute to malaria transmission. Attention was concentrated on dissecting the other Anophelines, special attention being paid to A. nili. Only two species were found with infected salivary glands. A. flavicosta had a crude sporozoite rate of 2·74 per cent, of the 73 dissected, and from 998 examples of A. nili a crude sporozoite rate of 0·80 per cent, was obtained. It was thought that as A. flavicosta was mainly zoophilous it was possible that the sporozoites in the glands were of malaria not of human origin. It appeared that where A. nili was common it could become a secondary vector, and on account of its marked exophilic nature it might prove difficult to interrupt transmisssion by this species.

The relatively recent increase in towns of C. p. fatigans and the almost virtual disappearance of C. nebulosus Theo., formerly the predominant Culicine, and the possibility that this change might have been initiated by the practice in recent years of using DDT larvicidal formulations and not oil, is discussed.

Morphological variation in nine characters of 157 clones of Myzus persicae(Sulzer) was examined by multivariate analysis. The clones were collected from peach, Prunus persica, the primary host and the secondary hosts tobacco, Nicotiana tabacum, cabbage, Brassica oleracea, sugarbeet, Beta vulgaris and pepper Capsicum annuum. The 156 clones originated from various regions of Greece, both in the north, where a large part of the population has an annual bisexual generation on peach, and in more southerly regions, where populations are predominantly unisexual. One clone was collected from tobacco in Caserta, Italy. All clones were laboratory-reared on potato. Canonical variate analysis, hierarchical cluster analysis and a non-parametric classification tree method both revealed morphological differences associated with the host-plant on which they were collected. The scores of the first two canonical variates separated the tobacco-feeding clones from those originating from other secondary host-plants. However, in tobacco-growing areas the tobacco-feeding form predominated in spring populations on peach, and was sometimes found on other secondary hosts. In addition, using cluster analysis, the clones from tobacco which were sampled in the most southeasterly region showed a relatively large phenotypic distance from those collected further north and west. Moreover, clonal phenotypes were affected both by host plant and by long-term parthenogenetic rearing. However, in spite of these effects, the tobacco form was generally distinguishable from aphids originating from other hosts, indicating that the difference must have a genetic basis. In separate analyses of the clones originating from secondary hosts no association was found between morphology and either life cycle category or colour. Discriminant analysis showed that 89% of 1723 specimens could be correctly classified into the two groups.

A method is described whereby tsetse visiting a stationary ox can be observed through a one-way glass screen in the presence or absence of man. Under the latter condition six times as many adults of Glossina pallidipes Aust. perch and feed on the ox. In G. morsitans Westw. most flies land in the head-down position and are unaffected by man's presence, but in the absence of man there is a four-fold increase in the number which land and feed in the head-up position. Calculations indicate that in the absence of man virtually all G. pallidipes adults attracted to the ox alight on it, and nearly all attempt to feed. Man's presence not only repels many tsetse completely but also inhibits the landing response of many of those that do approach the ox.

Questing individuals of Ixodes ricinus (L.) on a naturally infested moorland in Wales were censused every fortnight from January 1981 to October 1982 by blanket-dragging, and feeding ticks were counted on the sheep hosts. The seasonal activity patterns for ticks in all three stages were unimodal, with nymphs and adults active between March and July, and larvae active between April and August. This unimodal, as opposed to the usually described bimodal, pattern is explained in terms of the long cold winters and short summers of this field site. The survival time of questing nymphs was calculated from an analysis of their changing lipid content during the activity season to be a maximum of four months, which is consistent with the other field observations. The precise identification of the pattern of activity, as well as being essential for the application of appropriately timed control procedures, is necessary for the interpretation of the tick-host interactions under various control regimes that were applied.

Cyrtobagous singularis Hust. was recorded from Brazil, Paraguay, Uruguay and Argentina in association with six species of Salvinia (aquatic ferns). Field observations and laboratory studies in Brazil and Australia showed that C. singularis severely damaged S. molesta and that the weevil is suitable as a control agent for this weed in tropical and subtropical areas in Australia. In host-specificity studies using 46 plant species that occur in Australia, development of the immature stages took place only on S. molesta. Minor leaf scarring occurred on sweet potato when in contact with water, but starvation tests excluded this plant as a possible terrestrial host. Adults fed, but were unable to reproduce, on water lettuce (Pistia stratiotes). The high degree of host specificity indicated that establishment of this weevil in Australia is without risk to non-target plants. C. singularis was first released and became established in Australia in 1980.

Lutzomyia longipalpis (Lutz & Neiva), the vector of American visceral leishmaniasis (AVL), is much more abundant in animal sheds than in houses on Marajó Island, Pará State, Brazil. This difference in abundance is known not to reflect host preference. We show here that it also cannot be explained in terms of variable trapping efficiency, or insecticide application, and we exclude animal sheds as important daytime resting sites. In experimental sheds, the number of L. longipalpis increased markedly with the openness of the walls, though artificially large aggregations of flies could be generated in closed houses by using caged flies and hosts as attractants. We conclude that L. longipalpis tend to congregate at sites outdoors, including animal sheds, because these are the places where leks can most easily form on abundant, stationary (sleeping) and accessible hosts. These results help to explain why the seroprevalence of Leishmania chagasi infection is generally much higher among dogs than humans. They also indicate that human exposure to sandfly bites varies with the quality of house construction.

The activity of detoxifying enzymes (glutathione-S-transferases (GST), mixed-function oxidases (MFO), and esterases (EST)) and the presence of insensitive variants of target proteins (sodium channel and acetylcholinesterase) were examined in individual male and female codling moths. Twenty-nine populations from 11 countries and two laboratory strains were examined. Populations were classified as either unsprayed or sprayed. The ranges of enzyme activities across field populations varied 15-fold, 485-fold and fourfold for GST, MFO and EST, respectively. MFO was the only enzyme whose activity differed in a binomial classification of orchards based on their spray history. Few differences in enzyme activities were found due to sex among populations; and, in these cases, males had higher GST and lower MFO and EST activities than females. Activities of the three enzymatic systems across all populations were positively correlated. Populations from Greece, Argentina and Uruguay had significant percentages of moths with elevated GST and MFO activities. The co-occurrence of moths expressing both elevated MFO and low EST activities was found in conventional orchards from the Czech Republic and France. Chile was the only country where populations from treated orchards did not include a significant proportion of individuals with enhanced enzyme activity. The kdr mutation was found at significant levels in ten populations from five countries, including all French and Argentinean populations. The mutation in AChE was only detected in the Spanish population.

In Nigeria, shelled groundnuts are stored in sacks in covered warehouses and as pyramids in the open air. At the beginning of storage the nuts comprise approximately equal quantities of whole, split and broken nuts of a moisture content of 3·4 per cent. The sacks are exposed to direct hot sun whilst stacking.

The mean monthly maximum shade temperature in Kano ranges from 101°F. in April to 85°F. in January and August and the mean monthly minimum from 75°F. in May to 56°F. in January. Monthly maximum relative humidities range from 100 per cent, in August and September to 45 per cent, in February, and the monthly minimum from 71 per cent, in August to 12 per cent, in February. The range of mean relative humidity is 81 per cent, in August and 18 per cent, in February. Rains fall between April and September, 70 per cent, falling in July and August. Heavy falls are recorded on about 25 days.

Inside warehouses, the maximum monthly temperatures are 102°F. in May and 79°F. in January and February, and minimum temperatures are 81°F. in June, and 58°F. in February. In August the mean relative humidity range is 93 per cent, to 70 per cent. In December it is 34 per cent. to 20 per cent.

Just under the roof of a warehouse and on the surface of pyramids the diurnal range is very large.

A study, begun in 1966 at Edinburgh University, and completed during the ensuing 30 months at Muguga, Kenya, of the developmental periods of Rhipicephalus appendiculatus Neum. under controlled temperature and humidity was carried out to provide basic background information for an intensified FAO/EAVRO programme of East Coast fever research. Quantitative data are given on the preoviposition, pre-eclosion and, for larvae and nymphs, premoulting periods at three constant temperatures, 25, 21 and 18°C. The rate of development at all stages was accelerated by raising the temperature and retarded by lowering it. A “pre-immobilization period” which precedes the entry of engorged larvae and nymphs to the true moulting process also appeared to be temperature dependent. Development became very prolonged as temperatures fell below 18°C, being negligible at 15°C and having apparently ceased altogether at 9°C. Continuous exposure for more than two or three days to temperatures of 4°C and below were lethal to all engorged instars. Humidity (controlled at levels between 18 and 87% r.h.) had no influence on the rate of development. It is concluded that within limits of tolerable aridity, developmental periods would be completed within the times dictated by temperature regardless of the level of humidity or changes in the level of humidity. No suggestion of any diapause mechanism was discerned.

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.

In laboratory experiments in Australia under standard conditions, densities of the dung beetle Euoniticellus intermedius (Reiche) exceeding 150/1-litre pad of cattle dung were shown to suppress breeding of Musca vetustissima Wlk. The experiments also suggested that it was the effect of dung disturbance on the survival of eggs of the fly that led to suppression. Natural vaiation in the quality of cattle dung obscured but did not alter the effects of high beetle densities. The mobility of M. vetustissima in particular, obscured the relationship of its abundance to dung beetle numbers in the field in 1974–75 and 1975–77 an intial high level of flies was apparently reduced and suppressed by a seasonally late but otherwise similar level of beetle attack on dung pads.

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is considered a key citrus pest due to its role as vector of ‘huanglongbing’ (HLB) or citrus greening, probably the most economically damaging disease of citrus. Insecticidal control of the vector is still considered a cornerstone of HLB management to prevent infection and to reduce reinoculation of infected trees. The severity of HLB has driven implementation of intensive insecticide programs against ACP with unknown side effects on beneficial arthropod fauna in citrus agroecosystems. We evaluated effects of calendar sprays directed against this pest on natural enemy assemblages and used exclusion to estimate mortality they imposed on ACP populations in citrus groves. Predator exclusion techniques were used on nascent colonies of D. citri in replicated large untreated and sprayed plots of citrus during the four major flushing periods over 2 years. Population of spiders, arboreal ants and ladybeetles were independently assessed. Monthly sprays of recommended insecticides for control of ACP, adversely affected natural enemy populations resulting in reduced predation on ACP immature stages, especially during the critical late winter/early spring flush. Consequently, projected growth rates of the ACP population were greatest where natural enemies had been adversely affected by insecticides. Whereas, this result does not obviate the need for insecticidal control of ACP, it does indicate that even a selective regimen of sprays can impose as yet undetermined costs in terms of reduced biological control of this and probably other citrus pests.