Vaccinations are the mainstay of western preventive medicine, and they have been used to protect some crops against disease and insect pests. We consider rice as a model for protection using induced resistance since it is one of the most important staple crops and there have been significant new developments in: cross-resistance among rice insects, chemical pathways involved in induced resistance, sequencing the rice genome and expression of genes conferring resistance against rice insect pests. Insect attack has been found to cause lesions that kill planthopper eggs and early stages of gall midges. Damaged plants released volatiles that made them less likely to be chosen by planthoppers and more attractive to parasitoids. Chemical elicitors have been developed for dicotyledonous plants and these can induce resistance in rice, although rice does not fit models developed to explain signalling in dicots. For example, salicylic acid did not increase in rice after infection by pathogens and did not appear to be the mobile signal for induced resistance against pathogens although it was involved in induced responses to phloem-feeding insects. Jasmonic acid acted as a signal in some induced responses to pathogens as well as chewing insects. Many of the genes associated with induced resistance in rice have recently been mapped, and techniques are being developed to incorporate them into the genome of cultivated varieties. Attempts to control insect pests of rice will affect interactions with pathogens, predators and parasites, and other organisms in this agroecosystem.

Diadegma semiclausum (Hellén) (Hymenoptera: lchneumonidae), an exotic diamondback moth parasitoid, was released in two pilot areas (Werugha in Coast Region and Tharuni in Central Province) in Kenya. Fifteen month before release, observations on the diamondback moth, Plutella xylostella (Linnaeus), and local natural enemy population dynamics and pest damage were initiated in both areas and continued for three years after release. The P. xylostella population was bimodal with higher records during dry seasons. At Werugha, the peak population of P. xylostella was 16.8 per plant (October 2001); at Tharuni it was 12.8 (February 2002). Populations at Werugha declined from three months after release and decreased from 5.4 per plant (before release) to 0.8 (year 3 after release). Concurrently, average damage (1.9 to 1.5) (on a 0–5 scale), proportion of attacked plants (72 to 31%) and proportion of plants in damage group >2 (plants with head damage) decreased (21.4 to 5.3%), while total parasitism increased from 14.4 (before) to 52.5% (year 3 after release, 90% due to D. semiclausum). At Tharuni, D. semiclausum was only recovered 3 months after release. Average populations of P. xylostella declined from 5.9 per plant (before release) to 2.4 (year 3 after release) and damage scores from 2.3 to 1.7. The proportion of plants in damage group >2 declined from 39.7 to 4.5% while overall parasitism increased from 4.2 to 40.6% (98.3% by D. semiclausum). Four species of indigenous parasitoids (Diadegma mollipla (Holmgren), Oomyzus sokolowskii (Kurdjumov), Apanteles sp. and Itoplectis sp., all primary parasitoids) were almost completely displaced by D. semiclausum. Possible reasons for the different parasitoid development between the two release areas and the displacement of the indigenous species are discussed.

The efficacy of neem (1500 ppm azadirachtin (AI)), Delfin®WG™, a biological insecticide based on selected strain of Bacillus thuringiensis Berliner (Bt) subspecies kurstaki, and Cry1Ac protein, either individually or in combination, were examined against first to fourth instar Helicoverpa armigera (Hübner) larvae. Using an oral administration method, various growth inhibitory concentrations (EC) and lethal concentrations (LC) were determined for each bioagent. Combinations of sublethal concentrations of Bt spray formulation with azadirachtin at EC50 or EC95 levels not only enhanced the toxicity, but also reduced the duration of action when used in a mixture. The LC20 and LC50 values for Cry1Ac toxin were 0.06 and 0.22 μg ml−1, respectively. Bt–azadirachtin combinations of LC50+EC20 and LC50+EC50 result in 100% mortality. The mortality also was significant in LC20+EC20 and LC20+EC50 mixtures. These studies imply that the combined action is not synergistic but complimentary, with azadirachtin particularly facilitating the action of Bt. The Bt spray–azadirachtin combination is more economical than combinations that involve isolating the toxic protein, as the Bt spray formulations can be combined in a spray mixture with neem. These combinations may be useful for controlling bollworm populations that have acquired resistance to Bt as they may not survive the effect of mixture. Azadirachtin may be useful as a means of reducing the endotoxin concentrations in a mixture, to promote increased economic savings and further reduce the probability of resistance development to either insect control agent.

Lufenuron is a chitin synthesis inhibitor, which is able to impede Mediterranean fruit fly, Ceratitis capitata (Wiedemann), reproduction. In laboratory trials, following ingestion of lufenuron, the eggs laid by female Ceratitis capitata were prevented from hatching. In field trials in Valencia, Spain, lufenuron showed its effectiveness by reducing C. capitata wild populations and its continuous application to several generations of fruit fly resulted in increased pest control. This field trial was conducted in an isolated valley some 80 ha in size, over a continuous four-year period. In order to maintain the sterilizing effect in the field throughout the whole year, a new lufenuron bait gel was developed. This bait gel was introduced in to delta traps suspended in trees at a density of 24 traps ha−1, and these traps were replaced once a year during the field trial. Monitoring of the adult C. capitata population was conducted to assess the effects of the chemosterilant treatment. In the first year of treatment with sterilizing traps, a reduction of the C. capitata population was observed, indicating that the traps reduce the population right from the first generation. In the second, third and fourth years, a continuous and progressive reduction of the adult Mediterranean fruit fly population was observed. Therefore, the successive application of chemosterilization treatment has a cumulative effect on reducing the fly population year after year. Aerial treatment using malathion does not produce this cumulative effect, and consequently every year it is necessary to start again with the same number of flies as the year before. The possibility of using the chemosterilant method alone or combined with the sterile insect technique is discussed.

The oriental fruit fly, Bactrocera dorsalis (Hendel), is a major pest throughout South East Asia and in a number of Pacific Islands. As a result of their widespread distribution, pest status, invasive ability and potential impact on market access, B. dorsalis and many other fruit fly species are considered major threats to many countries. CLIMEX™ was used to model the potential global distribution of B. dorsalis under current and future climate scenarios. Under current climatic conditions, its projected potential distribution includes much of the tropics and subtropics and extends into warm temperate areas such as southern Mediterranean Europe. The model projects optimal climatic conditions for B. dorsalis in the south-eastern USA, where the principle range-limiting factor is likely to be cold stress. As a result of climate change, the potential global range for B. dorsalis is projected to extend further polewards as cold stress boundaries recede. However, the potential range contracts in areas where precipitation is projected to decrease substantially. The significant increases in the potential distribution of B. dorsalis projected under the climate change scenarios suggest that the World Trade Organization should allow biosecurity authorities to consider the effects of climate change when undertaking pest risk assessments. One of the most significant areas of uncertainty in climate change concerns the greenhouse gas emissions scenarios. Results are provided that span the range of standard Intergovernmental Panel on Climate Change scenarios. The impact on the projected distribution of B. dorsalis is striking, but affects the relative abundance of the fly within the total suitable range more than the total area of climatically suitable habitat.

The tribe Fordini is a fascinating group because of its complicated life history, primary host specificity and gall-forming characteristic. Different species produce galls with different morphology on different parts of the host plants. The EF-1α-based, COI-based and combined sequences-based phylogenetic trees with three algorithms MP, ML and Bayes all strongly suggest that Fordini is a monophyletic group with two clades corresponding to two subtribes, Fordina and Melaphidina, each also monophyletic. Some important morphological characters and primary host plants of aphids were mapped onto the phylogenetic tree to analyse the division of subtribes and to uncover at which level the aphids correspond to their primary hosts, Pistacia and Rhus. Results suggest that the division of subtribes in Fordini is closely related to host selection of aphids. The evolution of gall morphology and the probable driving force behind it in this tribe were also discussed. The Fordini aphids seem to have evolved towards a better ability to manipulate their host plant, induce strong sinks and gain high reproductive success. Galls in this tribe evolved mainly along two directions to attain this goal: (i) by enlarging the gall from small bag to spherical, even big cauliflower-like, and changing the galls' location or forming two galls in their life cycle (Fordina); (ii) by moving the gall position from midrib, petiole of the leaflet, and eventually to the common petiole of the compound leaf (Melaphidina).

Four species of Mesopolobus Westwood were reared as parasitoids of Ceutorhynchinae hosts in Europe during surveys in 2000–2004. An illustrated key is given to differentiate the four species, M. gemellus Baur & Muller sp. n., M. incultus (Walker), M. morys (Walker) and M. trasullus (Walker), plus M. moryoides Gibson, a parasitoid of the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham), in North America. Pteromalus clavicornis Walker is recognized as a junior synonym of M. incultussyn. n., and Pteromalus berecynthos Walker (also a junior synonym of M. incultus) is considered a correct original spelling. For Disema pallipes Förster (a junior synonym of Mesopolobus morys), a lectotype is designated. Mesopolobus morys is for the first time accurately associated with the seed weevil Ceutorhynchus turbatus (Schultze), a potential agent for classical biological control, of hoary cress, Lepidium draba L. (Brassicaceae), in North America. Mesopolobus gemellus is associated with another seed weevil, Ceutorhynchus typhae (=C. floralis) (Herbst), in pods of shepherd's purse, Capsella bursa-pastoris (L.) Medik. (Brassicaceae). Implications of the host–parasitoid associations are discussed relative to the introduction of species to North America for classical biological control of the cabbage seedpod weevil.

Diamondback moth (DBM), Plutella xylostella, is known for causing damage to Brassica crops and developing resistance to chemical and biological pesticides; it has become one of the most difficult pests to manage in many regions around the world. The only way to reduce reliance on pesticides is to maximize the role of natural control agents for integrated pest management programs and be able to incorporate the mortality from control agents into pest control decision-making. More than 90 hymenopterous parasitoids are associated with DBM worldwide; among them, Diadegma semiclausum, is a major endoparasitoid of P. xylostella. To optimize parasitism of pests in pest control decision-making, it is necessary to develop rapid and simple methods for distinguishing parasitized from non-parasitized larvae in the field. Here we report on a number of diagnostic tools to identify parasitized larvae. One is based on differential melanization reactions in hemolymph due to immune suppression in parasitized larvae. The lack of coagulation reactions in hemolymph provides a simple initial test, where squashing a non-parasitized larva onto nitrocellulose membrane traps chlorophyll-containing gut content on the membrane leaving a green dot of clotted gut material. However, in immune-suppressed parasitized larvae, the gut content was washed away in absence of coagulation reactions and the membrane lacks a green dot. This tool alone or combined with others, allows quick detection of parasitized caterpillars in the field. We further showed that the antibody MAb 9A5 can be used to detect D. semiclausum parasitized larvae of DBM in Western blots.

The sweet potato whitefly, Bemisia tabaci, harbors Portiera aleyrodidarum, an obligatory symbiotic bacterium, as well as several secondary symbionts including Rickettsia, Hamiltonella, Wolbachia, Arsenophonus, Cardinium and Fritschea, the function of which is unknown. Bemisia tabaci is a species complex composed of numerous biotypes, which may differ from each other both genetically and biologically. Only the B and Q biotypes have been reported from Israel. Secondary symbiont infection frequencies of Israeli laboratory and field populations of B. tabaci from various host plants were determined by PCR, in order to test for correlation between bacterial composition to biotype and host plant. Hamiltonella was detected only in populations of the B biotype, while Wolbachia and Arsenophonus were found only in the Q biotype (33% and 87% infection, respectively). Rickettsia was abundant in both biotypes. Cardinium and Fritschea were not found in any of the populations. No differences in secondary symbionts were found among host plants within the B biotype; but within the Q biotype, all whiteflies collected from sage harboured both Rickettsia and Arsenophonus, an infection frequency which was significantly higher than those found in association with all other host plants. The association found between whitefly biotypes and secondary symbionts suggests a possible contribution of these bacteria to host characteristics such as insecticide resistance, host range, virus transmission and speciation.

Recent studies show that Vetiver grass, (Vetiveria zizanioides (L.) Nash), may have potential as a dead-end trap crop in an overall habitat management strategy for the spotted stem borer, Chilo partellus (Swinhoe) (Lepidoptera: Crambidae). Vetiver grass is highly preferred for oviposition, in spite of the fact that larval survival is extremely low on this grass. The oviposition behaviour of female Chilo partellus moths was investigated by determining the amount and size of egg batches allocated to maize and Vetiver plants and studying the effect of rearing conditions and oviposition experience on host plant selection. Two-choice preference tests were used to examine the effect of experience of maize (a suitable host plant) and Vetiver plants on the oviposition choice of C. partellus. For both field-collected and laboratory-reared moths, no significant differences were found in the preference distributions between the experienced groups. It is concluded that females do not learn, i.e. that they do not change their preference for Vetiver grass after having experienced oviposition on either maize or this grass, which supports the idea that trap cropping could have potential as a control method for C. partellus. Differences observed between field-collected and laboratory-reared moths in the amount and size of egg batches laid on maize and Vetiver grass indicate that data obtained from experiments with laboratory-reared insects should be treated with caution.

Seasonal population fluctuation of the coffee leafminer, Leucoptera coffeella (Guérin-Méneville & Perrottet) (Lepidoptera: Lyonetiidae), led to an investigation of its natural mortality factors during the rainy season when the population level is low and during the dry season when population peaks occur. Life-table data were colleted from insecticide-free plots within a 3 ha coffee plantation on the upper, medium and lower canopy. Leafminer mortality was similar among the canopy parts but varied in the two seasons studied. During the rainy season, the generational mortality averaged 94.3%, with 50.2, 33.7 and 10.4% occurring during egg, larval and pupal stages, respectively. During the dry season, total mortality was 89%, with 13.2, 61.0 and 14.8% occurring during egg, larval and pupal stages, respectively. Marginal mortality rates during the rainy season were highest for physiological disturbances, rainfall and egg inviability; but, in the dry season, they were highest for predaceous wasps, physiological disturbances and parasitoids. Egg and larval stages accounted for most of the mortality variation in the rainy season, while the combination of larval and pupal mortality better described the generational mortality in the dry season. Variation in mortality during the rainy season was primarily associated with egg inviability, rainfall and parasitoids. In contrast, predatory wasps and physiological disturbances were the main factors associated with mortality variation during the dry season. These results suggest that weather conditions, natural enemies and plant quality attributes are the main determinants of the population dynamics of L. coffeella.

Bemisia tabaci biotype B is one of three genetic groups able to induce silverleafing in squash. Several earlier studies had observed that this physiological change was induced only through the feeding of juvenile whiteflies. This study uses adult males only to show that after 11 days the adult males were able to begin to induce silverleafing. Further, the response was density dependant with 120 adults inducing the first signs of silverleafing in 11 days, 90 adults in 13 days and 60 adults in 15 days.