Laboratory studies were conducted to evaluate the efficacy of neem, Azadirachta indica against corn earworm (CEW), Heliocoverpa zea fall armyworm (FAW), Spodoptera frugiperda sugarcane borer (SCB), Diatraea saccharalis southwestern corn borer (SWCB), Diatraea grandiosella maize weevil (MW), Sitophilus zeamais and larger grain borer (LGB), Prostephanus truncatus. Neem seed powder at the rate of 5 g and 10 g, and neem seed oil at the rate of 1 ml per kg of meridic diets, were incorporated into the diet of CEW, FAW, SCB and SWCB. Maize grain was treated with 5 and 10 ml neem seed oil per kg of grain and infested with adult MW and LGB. The presence of neem seed powder and neem seed oil in the diets significantly reduced the survival and growth of CEW, FAW, SCB and SWCB. Neem oil also had significant effects on the survival of MW. In the case of LGB the effects of neem oil, however, were not profound. Results indicate that neem has good potential to be used as a control agent for the CEW, FAW, SCB, SWCB and MW.
" Brevipalpus phoenicis (Geijskes), Acarina: Tenuipalpidae, infesting Persimmon—a new host record." , 38(1), pp. 107–108
Monitoring procedures with different trap designs and their proper location within the tree canopy were standardized for Archips pomivora Meyrick, a predominant tortricid infesting apple in Himachal Pradesh. Two synthetic pheromonal lures OBLR and FTLR were used over three seasons (1982-1984). Trap design had no significant influence on moth catch. Trap placement in the tree canopy was an important factor influencing the magnitude of moth catch. Traps positioned in the upper half of the canopy and near the periphery attracted significantly more moths. This pattern remained consistent in both smaller (< 4.0 m) and taller (> 7.0 m) trees. Almost all the moths were captured within the canopy, and traps placed outside attracted very few moths.
Caged experiments were carried out for two seasons (1987-88 and 1988-89) to investigate the potentialities of indigenous Coccinellidae in regulating aphid populations in wheat fields of Central Saudi Arabia. The results indicated that the use of Coccinella undecimpunctata L., the predominant predator in Gassim, alone or in combination with Adonia variagata Goeze and C. novemnotata Hbrst. at similar ratios as found in the fields, can satisfactorily control wheat aphids in a confined environment. Yields obtained from such coccinellid-treated wheat are not significantly different from those obtained from an uninfested control. Untreated aphid-infested wheat resulted in lower yields in both seasons (an average of 30.9% less than the aphid-free control for the two seasons). Head length and grain number per head were substantially lower in aphid-infested untreated control than in the coccinellid and the aphid-free treatments. Use of C. undecimpunctata alone or in combination with others resulted in increased yields by 35-6% and 39.7% in 1987/88, and by 38-5% and 27-9% in 1988/89. The aphids were kept significantly lower in the coccinellid treatments than in the infested untreated control, after the 3rd week of coccinellid introduction.
The use of groundnut oil and steam treatment were compared with pirimiphos-methyl treatment for control of Calloso-bruchus maculatus (Coleoptera: Bruchidae) in stored cowpea grain in The Gambia, West Africa. One susceptible and two bruchid-resistant varieties were compared under the different treatments. Steaming the cowpeas offered no permanent protection although it may be an effective sanitation technique. When used in conjunction with a bruchid-resistant variety, groundnut oil appears nearly as effective as pirimiphos-methyl applied to a local, non-resistant variety and the combination could offer a simple, effective method for protection of cowpea grain in similar regions.
The African rice gall midge, Orseolia oryzivora Harris and Gagne has become one of the major biotic constraints to rice production in Nigeria. A survey of gall midge distribution in Nigeria showed that the pest was common in the savannah and forest zones on rice grown under lowland ecologies. Endemic areas were identified which could serve as 'hot spots' for varietal screening. Indigenous parasitoids of the pest were identified as: Platygaster diplosisae Risbec, Aprostocetus pachydiplosisae Risbec and Aphanogmus spp. The dominant parasitoid was, however, P. diplosisae.
Eight viruses are reported from cowpeas in Africa. Three are beetle-transmitted (cowpea yellow mosaic comovirus, cowpea mottle virus (carmovirus?), and southern bean mosaic sobemovirus), two are aphid-borne (cowpea aphid-borne mosaic potyvirus and cucumber mosaic cucumovirus), two are whitefly-transmitted (cowpea golden mosaic virus (geminivirus?) and cowpea mild mottle carlavirus), and the vector of the eighth (sunn-hemp mosaic tobamovirus) is still unknown. Cowpea viruses are described from lowland, humid and sub-humid West Africa, as well as from mid-altitude ecological zones mainly found in eastern and southern Africa. Wherever facilities are limited and detailed characterization is not possible, a simple procedure using a combination of serology (agar-gel diffusion test), inoculation to test plants, and vector transmission studies, is proposed for the identification of the cowpea viruses reported so far from Africa. The possibilities of controlling these viruses are briefly discussed.
The insecticidal activity of neem, Azadirachta indica A. Juss., was tested on two major cowpea pests using different concentrations of aqueous extracts, and powders of both neem seed and kernel. The pests were larvae of Maruca testulalis Geyer (Lepidoptera: Pyralidae), the legume pod borer and Clavigralla tomentosicollis Stal (Hemiptera: Coreidae), the cowpea coreid bug. Ife Brown, an improved local cowpea variety, and IT84S-2246, a breeding line from IITA grain legume programme, were used in the study. Neem proved effective in acting as an insecticide and affected the rates of development of both pests at concentration as low as ca. 9% solution (wt/vol.). Imaginal survival was found to decrease with increasing neem concentration, but a point was reached where further increase in the amount of neem produced no significant changes in survival rates. Most bug nymphs died within 9 days of infestation but those which survived to adult in the 5% solution (wt/vol.) of the seed extract took almost twice the normal developmental time, and the emerging adults appeared weakened. While both the neem extracts and powder proved effective in suppressing development the former were more effective. This is the first report on the potential use of neem in the protection of cowpeas against C. tomentosicollis and M. testulalis.
A farm survey of 915 rice farmers in the Muda area showed that about 80% of the farmers own sprayers. The lever operated knapsack (LOK) sprayer is most popular. They are sold in over 30 brand names, mainly in retail and hardware shops. Sprayers owned are generally between 3-6 years old. About 76% of the farmers said that they are considering buying a sprayer in the near future. The most popular choice is the LOK sprayer with a tank capacity of about 3 gallons and a price range of between M$50-100 (US$19-38). Farmers are not aware of the newer spray methods, such as controlled droplet application, tractor-mounted sprayers and fogging machines. About 93% had never attended any training course on crop spraying or sprayer maintenance. In case of problems with sprayers, they normally do not seek help. Most farmers said they normally clean the sprayers using water from the irrigation canals after each use. Nozzles are also cleaned but are seldom replaced. It is apparent from the survey that there is an urgent need for more training programmes on spraying techniques and sprayer maintenance for rice farmers in the Muda area. The LOK sprayer is likely to remain as the main spray equipment and efforts should be made to improve them, both in research and in improving use efficiency. There is great variation in quality of the various brands available. Minimum standards should be set to prevent the sale of poor quality sprayers, which will contaminate the operators. Agricultural authorities should consider establishing centres or 'sprayer clinics', where farmers can obtain advice, repairs and training on spray equipment.
The distribution of Liriomyza spp. leafminer larvae on upper and lower surfaces of leaves at different nodes of main, lateral and sublateral stems were observed during two seasons on 0-4 ha experimental plots of tomato. The data indicate that the upper surface of the terminal three leaflets of the 7th leaf from the top of any stem may be used as a sample for evaluating densities of living or dead leafminer larvae. The relationship between the proportion of infested leaf samples and the number of larvae present was described by the equation Y = 1 - e-0.692x This relationship was validated in seven commercial fields of fresh market tomatoes.
Field experiments were done during winter seasons of 1988-89 and 1989-90 at Haryana Agricultural University, Hisar, India. Wild oat (Avena ludoviciana) was effectively controlled at 20 and 30 d.a.s. with 0.25 to 0.35 kg/ha tralkoxydim. The average reduction of wild oat population by 0.30 and 0.35 kg/ha tralkoxydim was 73.5 and 85.4%. Significantly better efficacy of tralkoxydim was obtained with spraying than broadcasting it with urea or sand at both the stages of application. An increase in the concentration of tralkoxydim enhanced control of wild oat. On an average of application times and methods, tralkoxydim at 0.25 kg/ha gave poor wheat yields. Tralkoxydim application at 30 d.a.s. produced significantly better crop yields than its earlier application.
Seventy-one identified, exotic, B. thuringiensis strains, representing 31 H-serotypes and 150 locally isolated B. thuringiensis strains, were screened for activity against second-instar C. partellus larvae. Differences in the toxicity of different subspecies to C. partellus larvae were revealed in the screening tests. Bioassays were performed on selected, toxic B. thuringiensis strains, and varieties entomocidus, kenyae and kurstaki (obtained from the USDA collection) were found to be the most potent strains tested, having calculated LC50 values of 2.00 x 10(5), 5.10 x 10(5) and 6.30 x 10(5) colony-forming units per gram (c.f.u./g) of artificial diet respectively. The results further highlighted the differences in the activity of different B. thuringiensis subspecies, and showed that there was variation in the potency of strains within the same subspecies. Thus the origin of the strain appears to affect its toxicity to a particular target species. A number of highly toxic B. thuringiensis isolates were recovered from soils, insect frass and dead insect material collected in Kenya. Isolates A-3, B1-1, A-C-2 and L1-6, recovered from dead Heliothis armigera larvae and insect frass, were the most potent strains recovered, with respective LC50 values of 7.00 x 10(4), 1.70 x 10(5), 2.30 x 10(5) and 2.60 x 10(5) c.f.u./g of artificial diet. These strains are therefore excellent candidates for use in a control programme against C. partellus.
Banana, an increasingly important crop in Kenya, is now threatened by the presence there of black leaf streak disease, caused by Mycosphaerella fijiensis. Following an epidemic of leaf disease in 1989, a survey was carried out in the major banana-growing areas of Kenya. Black leaf streak was recorded for the first time in Kenya but was absent from western Kenya.
Isolation of fungi from samples of Orobanche crenata Forsk. and Orobanche minor Sm. plants collected from Syria, Morocco, and France yielded 16 different species belonging to nine genera. The most common genera were Alternaria, Fusarium, and Ulocladium. Eleven species out of the 16 had not been known previously to have occurred on Orobanche. In the preliminary laboratory and field tests Ulocladium atrum Preuss. could infect and destroy underground tubercles and emerged shoots of O. crenata, provided temperature was around 20-degrees-C and the relative humidity between 50% and 80%. Its use as a potential biological control of Orobanche appears promising and should, therefore, be further studied.
Two field experiments on chemical weed control in Faro 41 upland rice (Oryza sativa L.) variety were conducted at a rainforest site near the National Cereals Research institute, Amakama Substation in 1989 and 1990. The herbicides tested were a co-formulated mixture of pretilachlor and dimethametryne at 1.5, 2-0 and 2.5 kg a.i./ha, a co-formulated mixture of piperophos and propanil applied at 3.16 and 3.95 kg a.i./ha, and Oxadiazon at 1.0 kg a.i./ha. Two hand weedings and a 'no weeding' treatment were included. The herbicides were applied 5 days after planting. All were safely selective to the crop. Most provided adequate weed control through 8-12 weeks after planting. Weeds controlled included Cynodon dactylon, Commelina benghalensis, Digitaria horizontalis, Eleusine indica, Panicum maximum, and Pennisetum purpureum as grass weeds. The broadleaf weeds were Emilia sonchifolia, Ageratum conyzoides, Portulaca oleraceae, Richardia brasiliensis, and Ipomoea involuncrata. The sedges Mariscus alternifolius and Cyperus esculentus were encountered in the plots. Pretilachlor-dimethametryne at 2.5 kg a.i./ha had the best weeding score. Two-year average grain yields of 1.7-2.6 t/ha were obtained from the herbicide treatments. With only 0.4 t/ha from the unweeded treatment, yield losses of more than 80% were recorded.
The results of field experiments showed that an improved crop package caused considerable reduction in density and dry weights of all categories of weeds and increased yield four times overtraditional farmers' practices in rained upland rice. Better land preparation (two ploughings at 15 d.b.s. and two at sowing), timely sowing (last week of June), application of fertilizer and an additional hand weeding markedly decreased the infestation of all categories of weeds in rained upland rice and helped in producing high grain yield. Improved variety and organic manuring had no effect on weed infestation but seemed to be essential for the yield improvement of upland rice.
Prophylactic fungicidal seed treatment, foliar fungicidal sprays and insecticidal sprays were compared in different combinations against the major pea pest complex. The severity of powdery mildew (Erysiphe polygoni), rust (Uromyces vinciae-fabae) and leaf blight (Ascochyta pisi), and damage caused by pod borer (Etiella zinckenella) and leaf miner (Chromatomyia horticola) were recorded at their lowest level in treatments where fungicidal and insecticidal treatments were combined. The highest yield of 15.88 q/ha (quintals per hectare) was obtained when seeds were treated with carbendazim and thiram combined with two fungicidal foliar sprays each of mancozeb and dinocap followed by a single insecticidal spray of endosulfan. Results indicate that a combination of seed treatment, fungicidal sprays and insecticidal spray was more successful against the pea pest complex and increased yields compared to fungicides and insecticides used separately. Seed treatment alone did not reduce the severity of the diseases studied.
Insecticides effective against pests of red ginger were identified. Disulfoton 15G and foliar applications of chlorpyrifos DF significantly reduced ants, banana aphids, and mealybugs. Foliar applications of acephate 75S.P, fluvalinate 2F and cyfluthrin 2E.C significantly reduced banana aphids and soft scales. As an insecticide barrier treatment, chlorpyrifos 20M.E.C totally eliminated ants and mealybugs. This study suggests the use of foliar insecticide sprays and/or insecticide barrier treatment to reduce insect pests of red ginger.
A key to 36 species of Tingidae commonly found on economically important plants from around the world is presented. The primary external characters used in the identification of tingids are discussed and illustrated, and habitus illustrations are provided for 29 of the 36 included species. The key also presents information on the host plants and geographic distribution of each species.
