Effects of cypermethrin + dimethoate and extracts of Piper guineense and Azadirachta indica on the pests and yield of cowpea, Vigna unguiculata

1990 ◽  
Vol 115 (2) ◽  
pp. 227-231 ◽  
Author(s):  
M. F. Ivbijaro ◽  
O. O. Bolaji

SUMMARYField trials were conducted in 1988 at the University of Ibadan to determine the effects of cypermethrin + dimethoate (Sherpa Plus®), the oil extract from ripe seeds of Piper guineense Schum & Thonn and the aqueous extract of ripe seeds of Azadirachta indica A. Juss on the pests and yield of cowpea. Cypermethrin + dimethoate was consistently superior to all other treatments in substantially reducing the population densities of Megalurothrips sjostedti Trybom and of Maruca testulalis Geyer, which are serious pests on flowers and buds, and in reducing the densities of four pod-sucking bugs. Pest population densities were also reduced by foliar sprays with A. indica or P. guineense extracts.Seed yield after treatment with cypermethrin + dimethoate was 0·99 t/ha, more than double the yield from other treatments. A marginal increase in seed yield compared with the control was achieved by foliar spraying with A. indica extract.

1991 ◽  
Vol 27 (4) ◽  
pp. 407-412 ◽  
Author(s):  
T. I. Ofuya

SUMMARYInsect infestation and damage in cowpea (Vigna unguiculala), planted sole or intercropped with tomato (Lycopersicon esculentum) was monitored in 1987 and 1988 in Akure, Nigeria. Infestation of cowpea byEmpoasca dolichiwas significantly reduced by intercropping with tomato in both years, except in the early season of 1988. Infestation of cowpea byOotheca mutabilis, Aphis craccivora, Megalurothrips sjosledti and Maruca testulaliswas not affected by intercropping with tomato in either year. Damage by pod-sucking bugs and Heliothis armigera was significantly higher in sole cowpea than in cowpea intercropped with tomato, in both years. Sole cowpea had a significantly lower seed yield than cowpea intercropped with tomato.Observaciones en cuanto a la infestación de insectos y daños en el caupí(Vigna unguiculata)sembrado en forma simultánea con tomate(Lycopersicon esculentum)en una zona de bosque tropical en Nigeria


Author(s):  
Elechi F. Asawalam ◽  
Ekemezie Constance

Field trials were conducted at Umudike, Nigeria, during the 2015 and 2016 cropping seasons to determine the efficacy of plant extracts from seven plant species against field insect pests of mung bean, Vigna radiata L. Wilczek. The extracts tested were obtained from scent leaf (Ocimum gratissimum), neem leaf (Azadirachta indica), bitter leaf (Vernonia amygdalina), garlic (Allium sativum), turmeric (Curcuma longa), plantain (Musa paradisiaca) peel and Negro pepper (Xylopia aethiopica). Karate (Lambda-cyhalothrin EC) at 50 mL was introduced as a check in the trials. The experimental design was a randomised complete block design (RCBD) with three replicates. Data were collected weekly on the insect population densities, yield and yield components. The results indicated that all the treatments were effective against mung bean insect pests (Aphis craccivora [aphid], Bemisia tabaci [whitefly], Amrasca biguttula biguttula [jassid] and Zonocerus variegatus[grasshopper]). There was a significant (p ≤ 0.05) reduction in the population of insects on the plots treated with plant extracts and karate in 2015 and 2016 cropping seasons. The population densities of grasshoppers in 2015 and whitefly in 2016 were significantly lower in the treated plots compared with the control plots. Azadirachta indica and C. longa extracts recorded the highest seed yield of 50.00 kg/ha and 42.33 kg/ha in 2015 and 2016, respectively. No significant differences were observed between the plant extracts and karate, which recorded significantly higher yields when compared with the control (23.30 kg/ha). All the plant extracts used exhibited insecticidal activity against the insect pests of mung bean. It is, therefore, recommended that these plant extracts can be used for the control of mung bean insect pests to achieve sustainable production, food security and quality.


2019 ◽  
Vol 50 (2) ◽  
pp. 104-109
Author(s):  
N.B. Izuogu ◽  
T.U. Olajide ◽  
E.K. Eifediyi ◽  
C.M. Olajide

Abstract Screenhouse and field trials were conducted at the University of Ilorin, Nigeria in 2013 and 2014 to investigate the effect of root knot nematode (Meloidogyne incognita) on the nodulation of five varieties of cowpea (IT89KD-288, IT82D-994, IT93K-452-1, T89K-391 and TT97 568-18). Half of the experimental plants were inoculated with Meloidogyne incognita eggs (n = 1500) while the remaining half served as uninoculated control plants. Data on growth and yield of cowpea, root gall, nodulation, and nematodes population densities in nodules were collected. Other parameters assessed included colour of dissected infected and uninfected nodules, texture of the nodules and varietal performance of the cowpeas. The results of both screenhouse and field trials were consistent in yield and visual observations of texture and colour. The yield of nematode-free varieties was significantly higher than that of M. incognita-infected ones. Infected nodules were dark brown in colour while the healthy ones were pink. For the field trials, nodulation counts in nematode inoculated plants were inversely proportional to the number of galls in their uninoculated counterparts in some varieties. Of all varieties, IT89KD-288 was most resistant to M. incognita. Due to high cost involved in the management of nematodes, especially with synthetic chemicals, variety IT89KD-288 is recommended for use in nematode endemic areas in Nigeria. Further study needs to be done on the histopathology of the infected and uninfected roots and nodules of these cowpea varieties.


1992 ◽  
Vol 119 (2) ◽  
pp. 211-222 ◽  
Author(s):  
S. N. Silim ◽  
P. D. Hebblethwaite ◽  
C. Jones

SUMMARYField trials at the University of Nottingham, UK, in 1979 and 1980 investigated the effect of moisture stress on the growth and yield of the leafless dried pea Filby. In the absence of drought, the crop photosynthetic area was increased and maturity delayed. Seed yield was increased by the production of a greater number of reproductive nodes and a reduced abortion of flowers and pods.In the second season, two sowing dates were also tested. Later sowing reduced the seed yield under the high and low moisture treatments by 14 and 33% respectively, due to an increased abortion of flowers and pods. The high moisture treatment reduced the water use efficiency (WUE) in this season and WUE was lower for the later sown crops, but there was no effect on WUE in the previous season.The seed yield and water use of pot-grown leafless peas were lower than were those of a nearisogenic line of leafed peas. Moisture stress reduced the yield of both phenotypes but the effect on the leafless pea was greater. Moisture stress imposed at flowering reduced yields more than it did at pod filling and there was an additive effect of moisture stress at both times.


2004 ◽  
Vol 52 (2) ◽  
pp. 157-163
Author(s):  
C. U. Egbo ◽  
M. A. Adagba ◽  
D. K. Adedzwa

Field trials were conducted in the wet seasons of 1997 and 1998 at Makurdi, Otukpo and Yandev in the Southern Guinea Savanna ecological zone of Nigeria to study the responses of ten soybean genotypes to intercropping. The experiment was laid out in a randomised complete block design. The genotypes TGX 1807-19F, NCRI-Soy2, Cameroon Late and TGX 1485-1D had the highest grain yield. All the Land Equivalent Ratio (LER) values were higher than unity, indicating that there is great advantage in intercropping maize with soybean. The yield of soybean was positively correlated with the days to 50% flowering, days to maturity, plant height, pods/plant and leaf area, indicating that an improvement in any of these traits will be reflected in an increase in seed yield. There was a significant genotype × yield × location interaction for all traits. This suggests that none of these factors acted independently. Similarly, the genotype × location interaction was more important than the genotype × year interaction for seed yield, indicating that the yield response of the ten soybean genotypes varied across locations rather than across years. Therefore, using more testing sites for evaluation may be more important than the number of years.


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1269
Author(s):  
David K. Mfuti ◽  
Amanuel Tamiru ◽  
William D. J. Kirk ◽  
Adeyemi O. Akinyemi ◽  
Heather Campbell ◽  
...  

The potential of semiochemicals to lure insect pests to a trap where they can be killed with biopesticides has been demonstrated as an eco-friendly pest management alternative. In this study, we tested two recently characterized male-produced aggregation pheromones of the bean flower thrips Megalurothrips sjostedti (Trybom), namely (R)-lavandulyl 3-methylbutanoate (major) and (R)-lavandulol (minor), for their field efficacy. Moreover, compatibility of these pheromones and two other thrips attractants, Lurem-TR and neryl (S)-2-methylbutanoate, with the entomopathogenic fungus (EPF) Metarhizium anisopliae ICIPE 69 has been determined. Our study revealed that the M. sjostedti aggregation pheromones have dose-dependent antifungal effects on the EPF viability, but showed no fungistatic effect at a field-realistic dose for attraction of thrips. (R)-lavandulyl 3-methylbutanoate had similar antifungal effects as neryl (S)-2-methylbutanoate 8 days after exposure; whereas, Lurem-TR had a stronger antifungal effect than other thrips attractants. In the semi-field experiments, all autoinoculation devices maintained at least 86% viability of M. anisopliae conidia after 12 days of exposure. Field trials demonstrated for the first time that (R)-lavandulyl 3-methylbutanoate increases trap catches. Our findings pave a way for designing a lure-and-kill thrips management strategy to control bean flower thrips using autoinoculation devices or spot spray application.


2021 ◽  
Vol 82 (1) ◽  
Author(s):  
Juliana Amaka Ugwu

Abstract Background Iroko gall bug, Phytolyma fusca Walker, is a major insect pest of Milicia excelsa (Iroko) seedling hampering its propagation in West Africa. Milicia excelsa is an indigenous forest timber tree in the tropical rain forest of West Africa with a very high value in international trade due to its wood quality. Sustainable management of P. fusca infestations on Iroko seedlings have not been achieved due to their cryptic nature and multivoltine generations. This study evaluated the residual and contact effects of crude ethanol and aqueous extracts of four plants (Azadirachta indica, Jatropha curcas, Piper guineense, and Aframomum melegueta) on adult P. fusca in the laboratory and field. Results All the extracts had residual effects and contact effects on adult insects in the laboratory at 75% and 100% concentrations of applications. Azadirachta indica, P. guineense, and A. melegueta gave 80–100% adult mortality at both concentrations in the laboratory; their efficacies were comparable to cypermethrin. The ethanol extracts of P. guineense and A. indica were more effective than other extracts in protecting the seedlings against Phytolyma infestations in the field. They significantly (p < 0.01) reduced infestation compared to other extracts and control. Ethanol extracts of the tested plant materials were more effective than their aqueous extracts both in the laboratory and field. Conclusion The results proved that P. guineense and A. indica extracts were very potent and promising in protecting Milicia excelsa seedlings against Phytolyma fusca infestations and they can be used in the early management of Phytolyma infestations in the field.


2016 ◽  
Vol 30 (3) ◽  
pp. 629-638 ◽  
Author(s):  
Ti Zhang ◽  
Eric N. Johnson ◽  
Christian J. Willenborg

Desiccants are currently used to improve lentil dry-down prior to harvest. Applying desiccants at growth stages prior to maturity may result in reduced crop yield and quality, and leave unacceptable herbicide residues in seeds. There is little information on whether various herbicides applied alone or as a tank-mix with glyphosate have an effect on glyphosate residues in harvested seed. Field trials were conducted at Saskatoon and Scott, Saskatchewan, Canada, from 2012 to 2014 to determine whether additional desiccants applied alone or tank mixed with glyphosate improve crop desiccation and reduce the potential for unacceptable glyphosate residue in seed. Glufosinate and diquat tank mixed with glyphosate were the most consistent desiccants, providing optimal crop dry-down and a general reduction in glyphosate seed residues without adverse effects on seed yield and weight. Saflufenacil provided good crop desiccation without yield loss, but failed to reduce glyphosate seed residues consistently. Pyraflufen-ethyl and flumioxazin applied alone or tank mixed with glyphosate were found to be inferior options for growers as they exhibited slow and incomplete crop desiccation, and did not decrease glyphosate seed residues. Based on results from this study, growers should apply glufosinate or diquat with preharvest glyphosate to maximize crop and weed desiccation, and minimize glyphosate seed residues.


1999 ◽  
Vol 133 (4) ◽  
pp. 403-407 ◽  
Author(s):  
V. C. UMEH ◽  
M. F. IVBIJARO

The efficacy of insecticides derived from two local plants was tested on termites infesting maize in maize–cassava–‘Egusi’ melon intercrops in two farmers' fields in south-western Nigeria during the 1989/90 and 1990/91 cropping seasons. The intercrops consisted of 40000, 20000, and 10000 maize plants/ha, with a fixed population of 10000 plants/ha of both cassava and melon. The insecticides were aqueous extracts of ripe seeds of neem (Azadirachta indica A. Juss) and the crude seed oil of Piper guineense Schum And Thonn, each at 10% concentration at the rate of 390 litres/ha and 18 litres/ha, respectively. On the plots treated with these natural insecticides, damage by termites [Microtermes spp., Macrotermes bellicosus Smeathman = nigeriensis Sjostedt and M. subhyalinus Rambur (Isoptera: Termitidae)] was significantly lower and maize yields higher than on the control plots. The mean percentage of maize stems attacked by termites (considering all categories of termite damage) in untreated plots during the trials ranged between 0–22% in 1989 and 2–46% in 1990. Planting densities did not significantly influence termite attack on maize. Cassava and melon plants or cassava tubers were not attacked by termites in any of the trials and their yields were not affected by insecticide treatments or planting density of maize.


1986 ◽  
Vol 22 (3) ◽  
pp. 243-251 ◽  
Author(s):  
B. R. Taylor ◽  
J. Y. Chambi

SUMMARYField trials are described in which the seed yield response of row-sown sesame to increasing plant population was examined, and in which row-sowing was compared with broadcasting at different seed rates. Maximum yields were obtained at an intended 200 to 250 × 103 plants ha−1 but yields were not greatly affected by a wider range of populations. Broadcasting, the normal local practice, gave yields slightly higher than those from rows 50 cm apart, the un-thinned rate of 800 × 103 viable seeds sown ha−1 yielded as well as treatments thinned to the optimum population, and double this seed rate, unthinned, gave the lowest yields, especially in rows.


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