Gigantometopus schuhi n.sp. is described as a new species from Borneo. The limits of the genus Gigantometopus are redefined.

Gigantometopus schuhi n.sp. is described as a new species from Borneo. The limits of the genus Gigantometopus are redefined.

Isometopus gharaati n. sp. and I. praetermissum n. sp. are described as new species from the Middle East and southernEurope. Isometopus praetermissumbelongs in the subgenus Isometopus Fieber whereas I. gharaati belongs in the subge-nus Jehania Distant; and with their description, the number of known species for the genus Isometopus Fieber in Europe and the Middle East is now ten. A key for separating all these species is presented.

The salivary glands of the cowpea pod-sucking bugs Anoplocnemis curvipes (Fabricius), Clavigralla tomentosicollis Stål, Clavigralla shadabi Dolling, Riptortus dentipes (Fabricius) and Mirperus jaculus (Thunberg) are described and illustrated. Extracts of the glands were assayed for the presence of proteinases, α-amylase, β-amylase and amyloglucosidase. The salivary glands consist of four-lobed principal glands and a tubular accessory gland, and they differ in shape and size among the different species except for the median lobe, which is more or less spherical. The sickle-shaped nature of the posterior lobe reported before for Riptortus linearis (Linnaeus) was also observed in R. dentipes , suggestive of a probable generic characteristic. Anoplocnemis curvipes has the biggest salivary gland, and it is followed by R. dentipes, M. jaculus, C. tomentosicollis and C. shadabi in descending order. Assays of the gland extracts revealed that the four digestive enzymes tested are present in the five coreoid species. Proteinases were preponderant (1.4–94.9 μg/ml), while amylases were detected in traces [(0.5–11.0) × 10 −3 μg/ml]. Proteinases may be largely responsible for the feeding damage caused by the coreoid species and their concentration in the glands of the different species correlates well with their known capacity to inflict pod damage and yield reduction in cowpea. Fourth instar nymphs of the different species also had higher concentrations of the digestive enzymes compared with their respective adults; and this correlates with the known ability of the nymphs to cause greater pod damage and yield reduction than adults.

Feeding trials were conducted on three (young, mid-fill and mature) developmental stages of cowpea Vigna unguiculata ssp. unguiculata pods in the screenhouse using fourth instar nymphs and adults of Anoplocnemis curvipes (Fabricius), Riptortus dentipes (Fabricius), Mirperus jaculus (Thunberg), Clavigralla tomentosicollis Stål and C. shadabi Dolling. Anoplocnemis curvipes was observed to be the most damaging coreoid species causing a yield reduction of 26.4-51.7% followed by R. dentipes (24.4-29.4%), M. jaculus (21.9-26.9%), C. tomentosicollis (17.9-22.4%) and C. shadabi (15.9-20.4%). The fourth instar nymphs of each pod-sucking bug species caused a significantly higher cowpea yield reduction than their respective adults. Similarly, infestation on young pods compared to mid-fill and mature stages resulted in significantly higher yield reduction. The results suggest that infestation levels of two fourth instar nymphs of A. curvipes or three fourth instar nymphs of the other four pod-sucking bug species per young pod should be adequate for screening of cowpea varieties for resistance to the coreoid bugs.

Isometopus vanharteni sp. nov., I. carinifrons sp. nov., Myiomma nigricollis sp. nov., and Paloniella ovata sp. nov. are described from the Republic of Yemen. A new name, Isometopus sudanicus is proposed for I. longirostris Akingbohungbe which is preoccupied by I. longirostris Josifov from Bulgaria. Paloniella ovata represents the first record of Paloniella Reuter from the Middle East.

Myiomma cobbeni n. sp. and Paloniella nodifrons n. sp. are described from the Ivory Coast. Additionally, M. maculata n. sp., Isometopus yemenensis n. sp. and I. quadrivittatus n. sp. are described from the Republic of Yemen. The new species from Yemen represent the first records of Myiomma Puton and the subgenus Jehania Distant of Isometopus Fieber from the Middle East.

O. nigeriensis Uvarov is widely distributed in the moist grassland habitats of Nigeria. Although this area is used for intensive agricultural activities, providing more than 90% of the grains needed in the country, the insect has been reported to cause only minor damage to agricultural crops while the closely related O. senegalensis is a serious pest of crops. The reason for the minor pest status of O. nigeriensis is unknown and only adequate study of the insect/host-plant relationship will provide some clues.Nymphs and adults of O. nigeriensis were reared on selected food plants (grasses) in the laboratory, this included Axonopus compressus, Cynodon dactylon, Eleusine indica, Seteria gracilipes, used singly and as a mixture of all four. Development of the nymphs was shortest when rearing was on a mixed diet: 60 d compared to 105 to 127 d for single host plants. Rearing the adults on S. gracilipes promoted faster oocyte development than the other treatments. The present pest status of the insect is discussed based on the data obtained.

AbstractA method for intensive screening of cowpea for resistance to Maruca testulalis (Geyer) is described. It is capable of ensuring uniform infestation and thus eliminating problems due to escapes. Four cowpea varieties earlier identified from field screening trials as resistant (TVU 946, TVU 1896 AG, H 51–1 and 2 AK) and three susceptible varieties (Ife Brown, H 144–1 and 58–185) were screened using this method. The results confirmed the status of the resistant varieties. Some effects on M. testulalis included, non preference for oviposition and larval feeding, and antibiosis manifested by reduced final larval instar weight, elongated pupal period and smaller sized emerging adult females.

Cowpea (Vigna unguiculata (L.) Walp) var. Ife Brown was infested with first instar larvae of Maruca testulalis at three crop growth stages: flower primodia, flower bud and open flower stages. Successful establishment of larvae was possible only at the flower bud stage. An infestation of two larvae per plant was optimal for detecting differences in flower and pod production and difference in yield between infested and uninfested plant.

The relative susceptibilities of 43 cowpea varieties to damage by Cydia ptychora (Meyrick) under chemical protection with monocrotophos, were investigated in field trials at lle-Ife, Nigeria. The results revealed significant varietal differences, with the moderately resistant varieties ER-7, BPL-3-1 and EW/1 consistently showing relatively low damage. These varieties may be useful in planning an integrated pest management programme involving minimum insecticide treatment.

The density responsiveness of larvae and adults of Cheilomenes lunata (Fabricius) preying on Aphis craccivora Koch was investigated under laboratory conditions where temperature and relative humidity were uncontrolled and fluctuated between 24-30°C and 43-90% respectively. The feeding rates of C. lunata were positively correlated with the population density of prey. The number of prey consumed daily by each predator stage tested, increased more steeply at lower, than at higher prey densities, exhibiting thus the Type II functional response. Fecundity of C. lunata females also increased to a plateau with increasing prey density.

Steam distillates of seven Nigerian plants, Lippia adoensis Hoschst, Azadirachta indica A. Juss, Monodora tenuifolia Benth, Piper guineense Schum & Thonn, Petiveria alliacea L., Citrus sinensis L. (variety Nigerian green orange), and Cymbopogon citratus L. were tested for acute toxicity on four major insect pests. The pests were larvae of Acrae eponina Cramer, adult cotton stainer Dysdercus superstitiosus (F.), the cowpea flea beetle, Ootheca mutabilis Sahlberg and the pod sucking bug Riptortus dentipes F. Essential oils of L. adoensis, M. tenuifolia and P. guineense were toxic to the insects. O. mutabilis was the most susceptible with LD50 of 0.15, 0.32 and 0.52 respectively for M. tenuifolia, L. adoensis and P. guineense, while R. dentipes was the least susceptible. There was cessation of feeding in A. eponina treated with essential oil of C. sinensis and P. alliacea.

Assessment of the damage potential of Cydia ptychora (Meyrick) was carried out in Ife Brown cowpea at different levels of larval infestation and different pod growth phases. The results showed that C. ptychora caused significant shrivelling in pods of Ife Brown cowpea when infested with either one, two or three first-instar larvae per pod at either the young or mid-fill growth phases, relative to the corresponding controls. A significant reduction in seed yield was also recorded in plants subjected to an infestation level of either one, two or three first-instar larvae per pod at both mid-fill and mature pod growth phases. Thus, an infestation level of one first-instar larva per pod at either the mid-fill or mature pod growth phases would be adequate for intensive screening of cowpea varieties for resistance to C. ptychora, using Ife Brown as a standard for comparison.

Cohort tests in screened cages confirmed that the cowpea varieties TVu 2994, TVu 3709, EW/I, BPL-3-1, ER-7 and Vita 5 have promising levels of resistance to Cydia ptychora (Meyrick). The resistance was found to be mainly explained by antixenosis with respect to oviposition. In no-choice tests in the laboratory, high larval mortality was recorded in TVu 3709 and BPL-3-1. Additionally, comparatively lighter-weight final instar larvae and adult females with reduced fecundity, fertility and longevity were reared from TVu 3709 and TVu 2994. Larvae reared on Vita 5 were slower in developing to adults than on other varieties; they were also relatively lighter in weight, while adults emerging from them showed reduction in size and fecundity. It is therefore concluded that resistance in TVu 3709, TVu 2994, BPL-3-1 and Vita 5 is partly due to larval antibiosis.

Journal Article Variation in Testis Follicle Number in the Miridae (Hemiptera: Heteroptera) and Its Relationship to the Higher Classification of the Family Get access A. E. Akingbohungbe A. E. Akingbohungbe Department of Plant Science, University of Ife, Ile-Ife, Nigeria Search for other works by this author on: Oxford Academic Google Scholar Annals of the Entomological Society of America, Volume 76, Issue 1, 15 January 1983, Pages 37–43, https://doi.org/10.1093/aesa/76.1.37 Published: 15 January 1983 Article history Received: 20 July 1981 Published: 15 January 1983

Four cultivars of cowpeas (Vigna unguiculata L. Walp.) were grown in 15 sets of conditions (environments) i.e. in several monthly plantings in each of three years. Data for seed yield were analysed to investigate the effectiveness of using planting dates in preliminary yield trials of new cultivars. Extremely significant environment mean squares and wide ranges of environmental indices (− 13.3 to 23.5) and seed yield (11.4 to 48.2 g plant−1) indicated real differences among environments. Stability analyses of the cultivar × environment interactions suggest that, where limited funds preclude the use of several locations, monthly plantings for two or more years could be used effectively in the preliminary evaluation of cultivars without losing much information on their relative ranking.

AbstractBracon ?hancocki (Wlkn.) is a larval ectoparasite of Cydia ptychora (Meyr.), a major pest of cowpea at Ile-Ife, Nigeria. Parasitism occurred in the field all the year round, varying from 0 to 65·9% and with the highest incidence from September to February. In the laboratory, the fecundity of the parasite was low, averaging about six eggs per female. The life-cycle was completed in ten days. Mating occurred soon after emergence, and the preoviposition period lasted about 2–3 days. Unmated females rarely laid eggs, and their life-span averaged six days as compared to 14 days for mated females. The female:male ratio was 2:1. The parasite rarely attacked previously paralysed hosts, and the preferred hosts were the older, larger larvae. A description of the egg and larvae is given.