The information available on the genetics, breeding, and utilization of host plant resistance to 14 of the most important species of maize stem-borers complex, their biology, and the damage done to the crop is presented.

The components necessary for implementing a programme for breeding for resistance to stem-borers in maize include: a colony of the pest(s), the capability to mass rear them, uniform artificial infestation methods, an array of the available maize germplasm or related species, rating scales and evaluation methods that permit identification of genetic resistance, knowledge of screening and breeding methods, and the personnel and resources to execute the programme.

The paper having emphasized the importance of each component, concludes with a discussion of several HPR programmes and the breeding methods being used in various areas of the world, to develop and utilize resistance to one or more maize pests, as a proven method for gaining increased management control over these pests.

Mythimna separata, the oriental armyworm, is a major agricultural pest of China. Five breeding regions are colonized successively by each generation of moths during the course of the year as a result of long-range migration. Three regions are colonized from south to north of China during the first half of the year and two in the second half of the year, possibly from north to south. The regularity of the seasonal displacements of the armyworm populations are an important basis for forecast and control. This paper presents a summary of research on migration of the oriental armyworm in China and discusses management strategies for this pest.

The biology of the African rice gall midge Orseolia oryzivora Harris and Gagné was investigated in screenhouse and laboratory studies, and its incidence on cultivated wet-season rice was studied in farmers' fields during the 2006 and 2007 rice-growing seasons at two localities in Nigeria. This insect is nocturnal, and mating takes place immediately after emergence. Both mated and unmated females lay eggs, with mated females laying on average 389 eggs each, and unmated females laying about 87 sterile eggs. The egg stage takes on average 2.5 days. Larval development takes 3.6, 3.3 and 3.0 days for the first, second and third instars, respectively, while the pre-pupal and pupal stages take 2.8 and 6.1 days, respectively. Adult females live for 48–78 h, while males live for 24–30 h. The life cycle of O. oryzivora is completed within 21–24 days under screenhouse conditions. The adult male is slender and about 3 mm long, while the female is more rounded with a 4 mm long body and a bright red abdomen. The insect produces unisexual progeny. Field incidence is low at the beginning of the rainy season, peaking with the peak in rainfall and humidity that concurs with the vegetative stage of the crop. The population of the midge declines as temperatures rise. In conclusion, prediction models may be developed based on weather parameters, to aid in forecasting the field incidence of O. oryzivora and its management strategies. Furthermore, it may be possible to reduce the damage caused by O. oryzivora to rice crops by altering planting period and taking into account environmental factors.

Sesamia calamistis Hampson and Eldana saccharina Walker larvae were reared at 25°C on pieces of stem from five indigenous African grasses. All five, Andropogon sp., Panicum maximum Jacq., Pennisetum polystachion (L.) Schult., P. purpureum L. and Sorghum arundinaceum (Desv.) Stapf. have been reported as host plants for one or both species. Larval survival, larval and pupal period and pupal weight were recorded and compared to values of these parameters for larvae reared on stems of maize and on artificial diet. S. calamistis larval survival was less than 10% on each grass species compared to 95% on artificial diet and 30% on maize stems. Larval period was similar on maize and the grasses, but was 50% faster on artificial diet. Pupal periods were similar for larvae reared on grasses, maize and artificial diet. Pupal weights were highest for larvae reared on artificial diet, followed by maize and then grasses. E. saccharina larval survival was less than 5% on each grass species compared to 60% on artificial diet and 19% on maize stem. Larval development was 25% faster on artificial diet than on maize or grasses. Larvae reared on grasses, maize and artificial diet had similar pupal periods. Pupal weights were lowest on grasses and highest on artificial diet.

Antixenotic and antibiotic components of resistance to the cassava mealybug, Phenacoccus manihoti Matt. Ferr. were evaluated in different varieties of cassava (Manihot esculenta Crantz), in Poinsettia (Euphorbia pulcherrima Wild), Talinum (Talinum triangulare Jack) and Faux-caoutchouc (hybrid of M. esculenta and M. glaziovii Mull. Arg.). Resistance, was estimated in the field on 25 varieties of cassava by means of varietal screening. Although we were unable to identify varieties ofcassava totally resistant to P. manihoti, there was evidence of partial resistances. Thus the Incoza variety is the most resistant, followed by the Moudouma and Zanaga varieties. On the other hand we found very susceptible varieties, such as Dikonda, Kataoli, 3M8 and 1M20. Laboratory evaluations of the antibiotic component of resistance, made by estimating the intrinsic capacity for increase rc, showed that the host-plantshave a considerable effect on the multiplying capacity of the mealybug. Indeed rc ranges from 0.038 (Poinsettia) to 0.160 (Ganfo cassava variety), i.e. a ratio of 1 to 4 between the two extreme values. If the cassava varieties alone are considered, the percentage of maximum variation is 20% between the Incoza (rc = 0.133) and Ganfo (rc = 0.160) varieties. The Incoza cassava variety is the most resistant, in terms of both antixenosis and antibiosis. Classification of the other cassava varieties, from the most to the least resistant, differs according to the resistant component under consideration. Poinsettia and Talinum both have a very strong antixenotic component, but their antibiotic component differs (rc = 0.038 and 0.150 respectively). Our results suggest that the resistance mechanisms of the host-plants of P. manihoti intervening in the fixation of the pest (antixenosis), are different from those acting on the development of the mealybug (antibiosis). We established significant correlations between the size of the mealybugs and their demographic characteristics for all the plants studied: the duration of the prereproductive period is shorter and the net reproduction rate is higher when the mealybugs are large-sized. These results are discussed in the context of an integrated monitoring programme.

Random amplified polymorphic DNA (RAPD) amplified by the polymerase chain reaction (PCR) was used to estimate the relatedness of three biotypes of brown planthopper, Nilaparvata lugens (Stål), from the Philippines. Each individual brown planthopper had a unique set of RAPD bands, but no bands were diagnostic for any one biotype. Brown planthopper types 1, 2 and 3 were genetically homogeneous. This supports results of other studies which conclude that brown planthopper biotypes are not sub-specific categories, but merely represent individual variation for virulence to rice cultivars.

The coffee berry borer (CBB), Hypothenemus hampei Ferrari, a recent invader to Hawaii, is impacting coffee growers by reducing yields and quality and increasing production costs. Monitoring strategies are needed to assess infestations and where control operations are warranted, and evaluate their effectiveness. To develop and validate a fixed-precision sequential sampling plan, an intensive CBB sampling programme was conducted in 17 small farms in Kona and Kau districts in the Big Island in 2016/17. At each location, 30 trees/ha were monitored at 2–4 week intervals. Results show that the CBB has an aggregated spatial distribution based on Taylor's power law parameters. According to Green's stop line formula, between 6 and 50 coffee branches per ha (sample unit) are required to estimate infestation rates of 1.5–2.5% infested green berries (suggested economic threshold) with a precision fixed at 10 to 25%. Concurrently, a modified strategy was tested on 14 farms, in which only infested green berries (not total) was counted. The standard and modified sampling methods were highly correlated (R2 ≥ 0.98), while the modified approach required on average only 35 min (27% less time) to complete, with an additional 24 min taken to observe the position of the CBB inside the berry. Our data also show that berry infestation rates of CBB prior to harvest were a good predictor of the total defects resulting in processed green coffee from these farms (Pearson's r coefficient of 0.82). Our findings support improved sampling for the CBB under Hawaiian conditions using a simpler and faster monitoring strategy based on counting green infested berries.

The circulatory system in insects is formed by a dorsal vessel (heart) that is a tubular structure that pumps haemolymph in the insect body cavity. Up until now, much is known about the structural organization of the heart in certain Brachycera (Diptera) (e.g. Drosophila). In contrast, little information is available regarding members of the Nematocera suborder (e.g. mosquitoes), in spite of their relevance to human health. Considering their importance, details of the heart morphology of six mosquito species (Aedes albopictus, Ae. aegypti, Ae. fluviatilis, Culex quinquefasciatus, Anopheles darlingi and An. aquasalis) were investigated by scanning electron microscopy (SEM). The heart of the adult mosquitoes, both males and females, consists of a dorsal tubular structure in association with pericardial cells located alongside the heart and alary muscles displaying ramifications that extend from the body wall to the heart surface. The SEM analysis also revealed in detail the organization of the heart, including paired valves on the heart wall (ostia). This study provides a detailed analysis of the mosquito heart microanatomy and, in our view, represents a significant contribution towards the understanding of structural–functional relationships associated with the heart of mosquito.

The distribution of the types of sensillae in the adult red palm weevil, Rhynchophorus ferrugineus (Oliv.) (Coleoptera: Curculionidae), was studied using scanning electron microscopy. Five types of sensillae can be identified on the antenna, with no apparent differences between sexes. These are: multiporous peg sensillae, sensillae trichoïdea (I and II); sensillae basiconica (type I, II and III) and sensillae styloconica. The distal segment of the maxillary palp bears 22 sensillae basiconica in the female, 13 in the male.The upper and lower incisor cusps of the mandibles of the male are relatively longer and more rounded, with an angle of 45° or more where the inner margins of the cusps meet. In the female, the upper and lower cusps are slightly shorter, with an angle of about 45°. In the buccal cavity of females, groups of finger-like sensillae basiconica of various length and shape project toward the centre of the oral opening. In the male, multiporous peg sensillae are found. Sensillae trichoidea are present on the ventral and dorsal sides of the first, second and third tarsal segments distally. These are much denser on the male than the female. On the terminal (9th) abdominal segment of the ovipositor, sensillae are distributed on the dorsal plate, medial plate, ventral plate and anal leaflets (paired). Sensillae of four types occur on the anal leaflets.

The effect of vegetation cover (millet) on the efficacy and conidial persistence of Metarhizium acridum (Driver & Milner) J.F. Bisch., Rehner & Humber was evaluated in semi-field conditions using breeding cages (2 × 2 × 1 m). A mixed population of third- and fourth-instar desert locust larvae, Schistocerca gregaria Forsskål, was used as a target. The insects were exposed in two different vegetation cover types classified as low (about 10%) and high (about 90%). Metarhizium acridum was used at a dose of 2.5 × 1012 conidia/ha in two different application volumes: 1 and 2 l/ha. Untreated insects kept in contact with treated vegetation were monitored to evaluate the persistence of conidia. The results showed that vegetation cover did not significantly (F= 1.320; P= 0.334) affect the efficacy of M. acridum. Under the high vegetation cover, the increase in the applied volume rate to 2 l/ha significantly improved the speed of mortality. Conidia persisted 6 days after treatment with a remarkable effect on untreated larvae exposed to the treated vegetation. In addition, the results of this study showed the efficacy of M. acridum in the low vegetation cover. With an important mass of vegetation, M. acridum conidia could persist even under high temperature conditions.

Information on termite assemblage in a young eucalypt plantation in Kerala was generated by running a single line transect and monthly sampling for 1 year. Through the transect sampling, 11 species were recorded under two families and four subfamilies. The subfamily Macrotermitinae dominated with eight species while the other three subfamilies were represented by a single species each. A temporal pattern of abundance was observed for the different active foraging species of termites in the monthly sampling. During April–November, a single species, Odontotermes obesus (Rambur), was the most abundant. During December–January, Microcerotermes fletcheri Holmgren & Holmgren was dominant, while Odontotermes feae (Wasmann) dominated during February and March. Rainfall was found to have a negative influence on the diversity of the active/foraging species of termites. Among the 14 species of termites collected, only four were found attacking eucalypt seedlings. Of the total termite samples collected, 40% belonged to the single species O. obesus, which was the major pest species representing 12 out of the 18 recorded incidences of termites feeding on roots of eucalypt seedlings. Among the species recorded, one was a new species and two were new records for Kerala State. The large number of non-pest species of termites indicates the beneficial role of these termites as efficient decomposers.

In the present study, body length and dispersal ability were examined in carabid beetles (Coleoptera: Carabidae) sampled in the Peruvian Andes along two altitudinal gradients: old-growth forest and anthropogenically disturbed region. Dispersal ability was estimated by the flight-wing condition (i.e. macropterous or brachypterous) and the cuticular length of the flight muscle (medial length of the metasternum). The relationship between body length and altitude for combined gradients varied by tribe; all possible relationships were found: positive; negative; no relationship. At the family level, a negative relationship between altitude and insect body length was found; this was predicted because of a decrease in the diversity of resources, habitat area and primary productivity, and the increase in the unfavourable environment observed at high altitudes. Flight muscle length was also highly variable among tribes; however, for combined gradients, a negative correlation with altitude was found at the family level. Some tribes were either completely macropterous or brachypterous, but at the family level, the percentage of brachyptery increased with altitude. We suggest two hypotheses that may explain the increased incidence of flightlessness observed with increasing altitude: constraints of energy use and reduced need for dispersal potential. At the family level, carabid beetles tended to have a greater body length and decreased brachyptery in disturbed regions compared with old-growth forests. Increased dispersal ability was expected because of the need to find a suitable habitat in disturbed areas. Observed relationships may depend upon which tribes are examined and whether the forest on an altitudinal gradient has been disturbed.

This paper describes the results of extensive rearing of shootfly species of the genera Atherigona and Acritochaeta from cultivated and wild Gramineae in Andhra Pradesh, India. Nineteen fly species were recorded from 41 graminaceous species including cultivated sorghum. Atherigona soccata, an important pest of sorghums in the Old World tropics, was reared from 22 host plants. Only cultivated and wild species of sorghum were important as hosts of this pest species. It was observed that alternative host Gramineae were of minor importance in the ‘carryover’ of Atherigona soccata through the off season, but the irrigated sorghum grown for fodder could be an important source of flies.

In general, shootflies of a particular species usually favored one graminaceous host above others. The numerically dominant fly reared from wild Gramineae was Atherigona falcata, which was recorded on 17 hosts, including sorghum. Other common species in Gramineae were Atherigona pulla, Atherigona oryzae, Atherigona punctata and Atherigona atripalpis, all of which were also reared in very low numbers from sorghum. Five new species of Atherigona were reared; three of these will be described shortly.

Larvae of Cirina forda (Westwood) (Lepidoptera: Saturniidae), a popular food insect in the southern parts of Nigeria were raised in the laboratory on cut foliage as well as on a growing Vittelaria paradoxa tree at the University of Ilorin, Nigeria. Comparative observations were made on the insect's biology and behaviour in both rearing systems in order to ascertain if the larvae could be reared in captivity on cut foliage. Egg eclosión began 24–48 hours after egg-laying and lasted 10 days. First instars initially aggregated after egg hatch, then migrated in single file to feed after approximately 12 hours after emergence. The first and second instars fed as an aggregate, while the third and subsequent instars fed separately. The first two instars did not exhibit any defensive response when disturbed, but the subsequent four instars emitted a green fluid which may act as a repellant to potential predators. High mortalities were suffered by the first and the penultimate instars. Results have shown that Cirina larvae could be easily reared artificially on V. paradoxa to serve as source of food for humans.

Different blends of five chromatographically prominent components of the pheromone emission of gregarious-phase mature desert locust Schistocerca gregaria (Forskål) (Orthoptera: Acrididae) males were bioassayed for their maturation-accelerating effects on immature counterparts. The blend of all five components, namely anisóle, veratrole, benzaldehyde, phenylacetonitrile and 4-vinylveratrole was as effective as the emission from live mature males in accelerating the onset of mating in immature males. Subtraction of anisóle had no significant effect but removal of any one of the other four components significantly reduced the acceleration potency of the resulting blends. The maximum reduction occurred in the absence of phenylacetonitrile which appears to be critical to the activity of the blend. The magnitude of reduction in maturation acceleration that resulted from the subtraction of the other three components suggests that, although present in lesser relative amounts, these compounds contribute significantly to the activity of the full blend. Some differences were found between the onset of integumental yellowing and mating which indicate that blends of slightly different compositions are involved in promoting these two physiological processes.

Studies on cannibalism by Heliothis armigera (Hubn.) larvae on nuclear polyhedrosis virus (NPV)-infected larvae and feeding on virosed cadavers indicated that feeding was significantly higher on 4-day-old virosed cadavers followed by 1-day-old cadavers than on healthy or NPV-infected living larvae. The data revealed that cannibalism was significantly higher on NPV-infected (3 days post inoculation) larvae than either healthy larvae or those which had been just inoculated. However, the extent of feeding was higher on healthy larvae (cannibalistic feeding) than on cadavers. Significantly more number of larvae became infected by NPV when they fed on NPV-killed cadavers than on NPV-infected living larvae. Some of the larvae which had fed on either virosed cadavers or NPV-infected larvae survived. But, the disease was expressed in the pupal stage. Pupal mortality was significantly higher in larvae which fed on NPV-inoculated larvae (3 days post inoculation). The multiple choice test to find out the feeding preference of the larvae showed that the larvae had a greater preference to feed on virosed cadavers than either the healthy larvae or the host plant. The role of cannibalistic behaviour in the dissemination of the virus disease under field conditions is discussed.

Rice yellow mottle virus (RYMV) is one of the most economically damaging diseases of rice in sub-Saharan Africa. It is found only in Africa and the surrounding islands, where it is transmitted by insect vectors such as Tricliispa sericea Guérin, Chaetocnema piala Chapius and Sesselia pusilla Gerst., (all Coleoptera) respectively within the subfamilies Hispinae, Halticinae and Galerucinae of the Chrysomelidae; Chnootriba (= Epilachna) similis Thunberg (Coleoptera: Coccinelidae); and Conocephahis longipennis de Haan (Orthoptera: Tettigoniidae). These vectors are leaf-feeders with biting mouthparts and are abundantly present on rice and grasses in irrigated lowland fields. Transmission of RYMV is mechanical as a result of feeding damage. However, the dynamics of virus spread and the role of the vector is poorly understood. A better understanding of RYMV epidemiology requires information on the distribution, biology, host range, nature of damage, and management strategies of the vectors. It is hoped that this review will be a useful source of information in the further development of integrated pest/disease management (IPM)in rice.

A strain of diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), adapted to peas was detected in 1999 in the export vegetable growing area south of Lake Naivasha in the Rift Valley Province of Kenya. The pea strain (DBM-P) was compared in laboratory studies to the normal crucifer strain (DBM-C). Whereas DBM-P performed comparably well on kales and peas, the cabbage strain (DBM-C) suffered heavy mortality on peas. Out of the 250 DBM-C first instars, only six reached adult stage on pea. In addition, larval development was prolonged by five days on peas as compared to kale, and larval growth was greatly reduced. Pupal weights of DBM-C survivors on pea were significantly lower (3.8 mg) than of DBM-P (4.6 mg) and those of both strains on kale (5.7 and 5.3 mg, respectively). Neonate larvae of the pea strain mined on both kale and pea but both the proportion of larvae mining and the number of mining days were lower than for DBM-C on kale. The latter failed completely to mine on pea.

A laboratory culture was started with the DBM-C survivors on pea and the performance of the progeny compared on kale and pea in three additional generations of selection. Larval survival increased from 2.4% in the first generation to 28.6%, 41.3% and 49.7% in the second, third and fourth generation, respectively. Pupal weight of larvae reared on pea increased with each generation of selection, but it remained significantly lower than of larvae reared on kale. In spite of the large differences in larval mining on the two host plants, performance on peas was not related to the ability of DBM-C to mine on pea but rather to the ability to initiate feeding without the normal stimuli present in crucifers. Pupal mortality for larvae from both hosts was similar when larvae of equal weight were compared, suggesting acceptable suitability of pea for larval development once the new host is accepted. The implications of these findings on adaptability of DBM to plants beyond its normal host range are discussed.

The susceptibility of maize germplasm from CIMMYT — Mexico, Malawi and Zimbabwe — to attack by the maize weevil, Sitophilus zeamais (Motsch.) was investigated under controlled temperature (28°C) and r.h. (70–75%). An index of susceptibility (I), derived from the numbers of F1 progeny and the mean development period was used as the basis for measurement of the susceptibility. The indices of susceptibility of the CIMMYT germplasm ranged from 9.25 for Rattray Arnold (I) 8149 to 14.48 for Poza Rica 7737. Of the 17 collections of Malawi local maize evaluated MLM#20 was the least susceptible (I = 10.72), while MLM#24 was the most susceptible (I = 13.25). The least susceptible of the Zimbabwean germplasm was a local collection of an indigenous maize, Variety 8 (I = 10.61), while the most susceptible was a hybrid PNR 6334 (I = 14.74). Further, the nine Mexican materials and a local hybrid SR 52 were evaluated under field conditions in small farmers' granaries. Rattray Arnold (I) 8149 and Population 68 were the least damaged and produced the lowest numbers of weevils. Maize classified as susceptible in laboratory tests also suffered high damage levels in on-farm storage trials.

Two β-glycosidases were purified from the termite Macrotermes subhyalinus (Rambur) workers by chromatography on gel filtration, ion exchange and hydrophobic interaction columns. The preparations were shown to be homogeneous on polyacrylamide gel. Both enzymes have a similar molecular mass (68 KDa) and optimum pH (5.4) but differ in optimal temperature and thermal stability. The β-glycosidases preferred β-fucosides to β-glucosides, β-galactosides and β-xylosides, and hydrolysed glucose-glucose-β-(1–4) linkages better than β-(1–3), β-(1–2) and β-(1–6) linkages. They did not hydrolyse saccharides such as melibiose, sucrose, lactose, xylobiose, melizitose, stachyose, lactose, raffinose, laminarin, arabinogalactan, carboxymethylcellulose, inulin, lichenan and starch. β-Glycosidase A and β-glycosidase B of M. subhyalinus workers are capable of catalysing transglucosylation reactions. The yields of glucosylation of hydroxyamino acid derivatives and phenylethanol, catalysed by the two enzymes in the presence of cellobiose as glucosyl donor, were lower than those reported previously with conventional sources of β-glycosidases. In addition, the optimum pH is different for the hydrolysis and transglucosylation reactions. On the basis of this work, it is proposed that the physiological role of β-glycosidase A and β-glycosidase B of M. subhyalinus workers is the digestion of di- and oligosaccharides derived from hemicelluloses and celluloses.