Species diversity of animals and plants is relevant to pest management in very different ways. Plant diversity provides sources of biologically active natural products and of genes for plant resistance. Animal diversity is involved in both harmful and beneficial interactions between crops and weeds or uncultivated land and in provision of potential biological control agents. The pest management implications of changes in biological diversity therefore need to be considered at a smaller scale in the management of cropping systems and on a larger scale in development programmes and national land use planning.

A schedule of insecticide spray combining two insecticides: Decis®(deltamethrin) and Systoate® (dimethoate) with four times of spray: 35, 45, 55 and 65 days after planting (DAP) was investigated in order to search for the most effective treatment against Maruca testulalis (Geyer) population on cowpea (Vigna unguiculata (L.) Walp). The local cowpea cultivar “Kpodjiguegue” was used to study the onset and fluctuation of M. testulalis larvae infestation on cowpea terminal shoots, flowers and pods. The trial was carried out during the 1985 early cropping season at Abomey-Cala vi. The treatments' effect on M. testulalis in the terminal shoots was not significant at the 5% level of probability because of the very low infestation of this part of the plant. In the flowers and pods, Decis® was better than Systoate® which failed in controlling this borer satisfactorily. In the unsprayed plots (i.e. control), the peak of the natural infestation occurred in the flowers towards 50 DAP and 65% of the flowers were injured. In the pods, up to 89% of infestation by M. testulalis larvae were observed 60 DAP. The lowest yield was recorded from the unprotected plots (322 kg/ha) whereas the treatment 0-Decis®Systoate®Decis® provided the highest yield (1367 kg/ha) and the highest returns.

Lentil seeds infested with Callosobruchus chinensis (Linnaeus) for 12–15 days were exposed to Dinarmus basalis (Rondani) alone, Anisopteromalus calandrae (Howard) alone, or to both species, at densities of 2, 4, 8, 16 and 32 insects. Intra-specific competition and host emergence decreased with increasing parasitoid density in both D. basalis and A. calandrae, but progeny production of the parasitoids and parasitoid-induced mortality (PIM) increased with increasing parasitoid density. Dinarmus basalis was much more efficient in parasitizing C. chinensis than A. calandrae. Emergence of D. basalis and A. calandrae, and the PIM were highest at a parasitoid density of 32. Parasitoid density and a combination of parasitoids significantly (P<0.01) affected the number and progeny sex ratio of emerged parasitoids. There were significant (P<0.01) effects of inter- and intra-specific competition on host mortality. Host mortality increased with increasing parasitoid density. Parasitoid combination and parasitoid density also significantly affected PIM.

Extracts of five plants, namely Argemone mexicana, Artemisia absinthium, Cassia occidentalis, Cymbopogon citratus and Siegesbeckia orientalis were tested for their antifeedant and insecticidal effects on third-instar larvae of the cabbage webworm, Crocidolomia binotalis, which is presently one of the most important pests of cruciferous crops in Mauritius. All the five plant species investigated showed significant antifeedant properties, with A. mexicana showing the highest control potential of the five plant species studied against C. binotalis.

Experiments were conducted during two consecutive years (1983 and 1984) on irrigated rice, in the Southwest of Burkina Faso, in order to monitor the seasonal incidence of the rice gall midge, Orseolia oryzivora H. et G.

The damage incidence is the same whatever the date of planting within the rainy season. Attacks are low during the early growth phase of the rice plants (0 to 3% of “silver shoot”), and increase gradually to reach spectacular levels (20 to 55% of “silver shoot”) between 70 and 90 days after transplantation, after which there is decreased attack.

Parasitism is an important check on the larval population of the pest; up to 77% of parasitized larvae were observed. However, this parasitism due mainly to microhymenoptera, Platygaster diplosisae Risb. and Tetrastichus pachydiplosisae Risb., gets established late.

These results could contribute significantly in developing an IPM process on irrigated rice in Burkina Faso.

Based on a semi-synthetic diet, a standard rearing method for the cotton bollworm, Hetiothis armigera Hübner, is described. The diet is composed of chickpea (Cicer arietinum) flour, yeast powder, sucrose, ascorbic acid, cholesterol, choiine chloride, wheat germ oil, vitamin mixture and a combination of preservatives. A plastic container for individual rearing of the cannibalistic larvae and a cage for mating of adult moths are described. After inoculation with the neonate larvae, development of the different stages was synchronouson this diet. The larval and pupal development period was 14.3 ± 1.2 and 11.7 ± 0.82 days, respectively. Females reared on this diet produced an average of 2000 eggs. Adult longevity was 22 days. The female moths retained their oviposition rhythm even after 3 years of laboratory rearing. A method for introduction of wild populations into the laboratory culture is discussed. The reliability of the technique was checked by monitoring the insects' performance for at least 25 generations.

Life table statistics on the age-specific fecundity and survival of female Spilosoma obliqua Walker reared on sunflower showed a net reproductive rate of 513.6 eggs per female, with approximate generation time of 48.2 days. Its intrinsic rate of increase (rm) was 0.1295, meaning that its population could double in 5.35 days. Spilosoma obliqua on sunflower was parasitised by Apanteles obliquae, Glyptapanteles creatonoti and Carcelia sp.

Conessine, the steroidal alkaloid of Holarrhena antidysenterica Wall, possesses a wide range of activities against four insect species viz. Aedes aegypti, Dysdercus koenigii, Spodoptera litura and Pieris brassicae. In D. koenigii the compound inhibits the egg hatching of treated adults and nymphs. In Ae. aegypti the larval developmental periods are extended, resulting in a high mortality rate. Such effects are produced at very low dosages of 0.5 to lOppm. Antifeedant activity is observed against larvae of S. litura and P. brassicae at concentrations of 0.005 to 0.2 % of conessine.

In studies aimed at optimizing the substrate for rearing Helicoverpa armigera (Hübner) under laboratory conditions, the noctuid's oviposition behaviour was studied in the laboratory using pigeonpea leaves, muslin cloth, tissue paper and cotton wool as oviposition substrates in free-choice and no-choice tests. Egg counts revealed the moth's preference for oviposition substrate, in descending order, to be cotton wool, pigeonpea leaves, tissue paper and muslin cloth. The preference index of cotton wool was 65% higher than the least preferred substrate, muslin cloth. A total of 300 eggs per female were laid in the free-choice tests, while 200 were laid in the no-choice assays.

Root-knot nematodes (RKN) are serious pests of tomato production in Kenya. Accurate identification of the plant parasitic nematodes is important for their effective management. A study conducted to assess their prevalence and identify RKN occurring on tomatoes in Central Kenya showed infestation of the crop in all the three districts. Of the total sampled plants (N = 900), the RKN infestation level ranged from 28 to 62%. RKN disease severity ranged from 2.5 to 5.3 in all the locations. Meloidogyne incognita,M. javanica and M. arenaria were the only species found infesting tomatoes in these areas. Female nematodes sampled from the symptomatic root system that had root galls characteristic of RKN were analysed by isozyme phenotypes of esterase (EST) and malate dehydrogenase (MDH). EST phenotype was polymorphic and enabled identification of the three different species, while MDH was monomorphic. Polymerase chain reaction-restriction fragment length polymorphism with region between mitochondrial cytochrome oxidase subunit II and large subunit ribosomal RNA (mtDNA COII-LSUrRNA) using HinfI showed that all isolates of M. incognita could be digested into three restriction fragments of about 1300, 400 and 100 bp, except for one species that showed an additional restriction site, giving four fragments of 900, 420, 380 and 100 bp. The 1800 bp PCR product of M. javanica was not digested by HinfI. Meloidogyne arenaria (EST phenotype A1) PCR product was digested into two restriction fragments of about 1700 and 100 bp, while M. arenaria (EST phenotype A2) had two restriction fragments at 1100 and 100 bp.

The purification and characterization of rhodanese, an enzyme that catalyses the detoxification of cyanide, from the gut of the variegated grasshopper (Zonocerus variegatus L.) were carried out to understand the biochemical basis of the survival of this grasshopper living on cyanogenic plants such as cassava. All experiments, including enzyme assay, were carried out at room temperature and all buffers contained 10 mm sodium thiosulphate to stabilize the enzyme. Grasshoppers were caught alive from a cassava farm within the locality and kept frozen until analysis. Each grasshopper was dissected and the gut was removed quickly. Approximately 102 g of the gut were homogenized in three volumes of 0.1 m acetate glycine buffer (pH 7.8) containing ɛ-amino-n-caproic acid. The supernatant was collected by centrifugation at 12,000 rpm, for 30 min at 40 °C. The enzyme was purified to homogeneity by a combination of procedures such as ammonium sulphate precipitation, ion-exchange chromatography (CM-Sephadex and DEAE-Sephadex), gel filtration (Sephadex G-75) and Agarose-Blue affinity chromatography. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS–PAGE) and non-SDS–PAGE were used to ascertain the purity of the enzyme. The native and subunit molecular weights of the enzyme were determined by gel filtration on a Bio-Gel P-200 column and SDS–PAGE, respectively. Kinetic parameters were determined by using varying concentrations of one of the substrates at a fixed concentration of the other, and vice versa. Furthermore, the effects of temperature, pH and cations on the activity of the enzyme were investigated. The purified enzyme had a specific activity of 51.7 μmol thiocyanate formed/ml/min/mg protein (U/mg protein) with a yield of about 29%. The apparent molecular weight of the enzyme estimated by Sephadex G-75 gel filtration was 35,400 ± 482 Da and its subunit molecular weight determined by SDS–PAGE was 33,000 ± 212 Da. The Km values of KCN and Na2S2O3 were found to be 29.63 ± 02.87 and 26 ± 03.04 mm, respectively. An optimum pH and temperature of 7.0 and 35 °C, respectively, were obtained for the enzyme. The results of enzyme inhibition showed that the activity of the enzyme was not affected by NH4Cl, MgCl2, CoCl2, CaCl2, MnCl2, NiCl2 and SnCl2, but inhibited by ZnCl2 and BaCl2. In conclusion, these results suggest that the survival of Z. variegatus depends on the presence of the enzyme rhodanese, which shows high activity and has suitable kinetic properties in the gut of the grasshopper that feeds mainly on cassava leaves which are cyanogenic.

Changes in the physiological status of the host rice plant had a profound effect on wing morphism in the brown planthopper, Nilaparvata lugens (Stål). Significant increases in macroptery in the hopper progenies reared on senescent or hopperburned hosts occurred mainly because of a general decline in the host's nutritional status and allelochemic factors. Starvation of young nymphs on nutritionally-depleted hosts probably inhibits the secretion of juvenile hormone by the corpus allatum, suppressing brachyptery and expressing macroptery. Also, any juvenilizing effect of the host's allelochemics would tend to dissipate with the host's senescence. Therefore, the proportion of macroptery in the hopper progeny developing on the rice host plant is determined by the extent of depletion of the host's nutritional allelochemic factors. The observed significant increase in macroptery at a density of 50 or more hoppers per plant may have also been mediated through the host plant. Brown planthopper progenies of macropterous and brachypterous Biotypes 1, 2, 3 and the field population differed in their expression of macroptery probably because of their inherent differences in sensitivity to macropteryinducing stresses.

A survey of entomopathogenic nematodes (EPNs) belonging to the families Steinernematidae and Heterorhabditidae was conducted in three municipalities on the Pacific coast of the State of Colima, México, to determine their occurrence and recovery frequency and predominant plant species in cultivated and non-cultivated habitats. Nineteen soil samples were collected: seven from non-cultivated habitats and 12 from habitats or areas cultivated mostly with fruit and grain crops and grasses. Of the 19 soil samples, 14 were positive for EPNs; the total prevalence was 73.7%. From the 14 positive soil samples, 12 steinernematid isolates (85.7%) and two heterorhabditid isolates (14.3%) were recovered. Irrespective of the locations, EPNs from the genus Steinernema were recovered from the three municipalities; EPNs from the genera Steinernema and Heterorhabditis were recovered from Armería and Ixtlahuacán. Only steinernematid isolates were recovered from non-cultivated habitats. Most of the isolates were recovered from cultivated habitats, and our results suggest that there is a higher prevalence of EPNs in cultivated soils.

Antheraea assamensis (Helfer, 1837) is a sericigenous insect with distinct coloration, namely green, blue, orange and yellow in their larval stages and these are multivoltine in culture. However, wild morphs with diapause are found in dense forests. In this study, the wing venation and its variation in A. assamensis were analysed using traditional as well as landmark-based morphometric methods. The venation patterns are reviewed and significant changes in veins recorded. The samples were analysed using geometric morphometric methods and other conventional statistical methods. Landmark-based data were measured among selected veins and the centroid sizes, procrustes to tangent distance of different veins were analysed. Results show significant differences in some of the veins among the intraspecies of A. assamensis. The results suggest that both visual comparison as well as a quantitative approach in A. assamensis may lead to unsound taxonomic conclusions at intraspecies level.

Pollination in the genus Ceropegia L. (Apocynaceae: Asclepiadoideae–Ceropegieae) in East Africa is discussed based on field observations and herbarium studies. All inferred or confirmed pollinators are small, mostly female dipteran flies, c. 2.5mm long, which carry pollinaria on their proboscis. Identified putative pollinator flies belong to families Milichiidae, Chloropidae and Ceratopogonidae. The most important factors for an insect to effect pollination appear to be the appropriate overall size, i.e. small size of c. 3×;3mm at most, and appropriate mouth parts, i.e. extendible probosces with suitable surfaces and adjacent pads on which a pollinarium can attach. The complex and diverse floral morphology of the tubular flowers and their disposition as well as other commonly occurring features namely, diverse interior and exterior coloration, diverse scents, secretions such as nectar and water droplets, vibratile corolla lobes and hairs, specialized hairs, interior sculpturing, sliding zones and differential lighting within the flower are important mechanisms for attracting and detaining insect pollinators.

Tree-hole phytotelmata encompass the internodal water pools that form in many species of bamboo (Gramineae). Using bamboo traps, we sampled macroinvertebrate communities in a habitat within the subtropical cloud forest of Henri Pittier National Park, Rancho Grande, north-central Venezuela, and quantified the temporal differences in their abundance and composition. In total, 1024 invertebrates were collected during the 7 months between February and August 2008. The insect orders Diptera and Coleoptera were abundant, particularly Culex (Anoedioporpa) conservator Dyar & Knab, Culex (Culex) mollis (Dyar & Knab), Wyeomyia (Wyeomyia) arthrostigma (Lutz) and Toxorhynchites (Lynchiella) theobaldi (Dyar & Knab). The traps also contained predators, detritivores and collectors (filtering and gathering). Macroinvertebrate abundance in the traps was higher during the rainy season. This observation was attributed to a greater abundance of Ephydridae, Blattaria and Culicidae during wetter months, and an increased availability of potential new breeding sites in the environment, which resulted in increased adult eclosion, and higher rates of oviposition in the bamboo traps. Temporal differences in pH and dissolved oxygen levels of trap water were observed.

Total and differential haemocyte counts following starvation and feeding resumption, ventral nerve cord transection, and brain implantation followed by methoprene application and 20-hydroxyecdysone injection were studied in Danaus chrysippus (Linnaeus) larvae. The results revealed that initial starvation and transection of the ventral nerve cord before the fifth abdominal ganglion in fifth instars of D. chrysippus led to a reduced total haemocyte count, on the one hand, and to a higher variation in percentage of different haemocyte types, on the other. While feeding resumption, brain implantation and 20-hydroxyecdysone treatments reversed the effect of starvation and nerve cord transection, methoprene application produced a decline in total number of haemolymph cells.

Termite damage to annual crops on smallscale farms was surveyed in eight areas in southern Malawi during 1989/90 to 1991/92. The most frequently grown crop was maize, followed by pigeonpeas, Phaseolus beans, cotton, cowpea and groundnuts. Twenty-seven species of termites were found attacking crops. The most numerous and widely distributed were several species of the Macrotermitinae, including Ancistrotermes latinotus, four species of Macrotermes, four species of Microtermes, three species of Odontotermes and Pseudacanthotermes militaris. All species damaged maize but only a few damaged bambara, cassava and banana. The damage appeared to be more frequent in dry areas than in wet ones.

The seasonality and behaviour of tabanids were studied in the Planalto Serrano of Santa Catarina State, Brazil. From March 2007 to February 2009, a total of 915 tabanid flies from 15 species and six genera were collected on an individual horse. The number of tabanid species varied from zero during autumn/winter to ten in summer (December–February). Dichelacera alcicornis Wied. (62.1%) was the most abundant species followed by Chrysops fusciapex Lutz (6.7%) and C. patricia Pechuman (5.9%). Peak catches occurred during the summer (December–March). The landing behaviour varied by genera: Chrysops (100%) preferred the head, Dichelacera (56.3%) the flanks, and Poecilodera (100%), Acanthocera (100%), Tabanus (58.8%) and Fidena (48.7%) the limbs region. This is the first work on tabanids in the Santa Catarina State, Brazil.

Greenbug, Schizaphis graminum (Rondani), an important vector of barley yellow dwarf mosaic virus, is a major pest of cereals in many countries. A preliminary survey conducted in the Punjab and North Western Frontier Province of Pakistan revealed medium to heavy infestations at Charsadda (density 12 apterous greenbugs/25 plants), Sher Shah (Multan) (density 33) and Malkot (Murree) (density 114). However, it was found in small numbers at many other locations.

A culture of greenbugs collected from Charsadda, was established on susceptible wheat cultivar Faisalabad-83 at 27 ± 3°C, 60% r.h. and 16:8 hr day:night regime. A seedling bulk test using local and exotic host differentials indicated that DS-28A and Largo wheat were susceptible, whereas Amigo wheat, Post and Will barley were resistant. This indicates that the population of greenbug from Charsadda culture was different from greenbug biotypes occurring in the USA. Therefore, it was designated as biotype PK-I for future reference.

Of the 44 recommended wheat cultivars in Pakistan, Punjab-85 was found to be resistant (visual damage rating (DR) 3 at 0 to 9 damage scale; 0, healthy; 9, dead). Faisalabad-85 had a DR of 4, PARI-73, Sandal and Yecora had a DR of 5, and PAK-81, WL-711, Sutluj-86 and Nuri-70 had a DR of 6. All the remaining cultivars were highly susceptible to greenbug (DR ≻ 6).

Three tests, namely, antixenosis (non-preference), antibiosis and tolerance, were conducted to determine the nature of resistance in selected entries. In the antixenosis test, PARI-73, WL-711 and Yecora were found to be the least preferred. The lowest fecundity (antibiosis) of the greenbug was on Punjab-85. In the tolerance test, the lowest damage was recorded on PARI-73 (DR= 4.1), followed by Sandal (DR= 4.8) and Punjab-85 (DR= 4.8). These three tests indicated that resistance in Punjab-85 is mainly due to antibiosis and a low level of tolerance.

During this study 439 native wheat germplasm lines were also tested. Of these, 16 germplasm lines (PAK 15081, PAK 15115, PAK 15139, PAK 15242, PAK 15433, PAK 15479, PAK 15481, PAK 15519, PAK 15992, PAK 15994, PAK 15995, PAK 15997, PAK 16007, PAK 16008, PAK 16010 and PAK 16190) were found to have a high level of resistance (DR ≺ 3). Of the test entries, 114 were moderately resistant (DR= 4–6) and the remainder were susceptible (DR ≻ 6) to greenbug. The germplasm lines found resistant may have different genes for resistance which can be exploited in breeding programmes.