Field evaluation of cowpea cultivars (Vigna unguiculata[L.] Walp.) for resistance to flower bud thrips (Megalurothrips sjostedtiTrybom) (Thysanoptera: Thripidae)

Stability and extent of resistance of cowpea lines to flower bud thrips in Uganda

“…Thus, the selection of resistant cowpea varieties should not be based on the number of thrips counted per flower. Contrastingly, Alabi et al (2003) found a strong positive correlation (r=0.86) between thrips damages scores and thrips counts in flowers in Nigeria. This kind of variation among studies are always attributed to genotype and environmental factors (Olawale and Bukola, 2016).…”

“…Similar findings were reported by Omo-Ikerodah et al (2009) in Nigeria under field conditions, while evaluating the resistance of Sanzi, and TVu 1509 to flower thrips. In contrast, Alabi et al (2003) in Nigeria and Abudulai et al (2006) in Ghana, reported that the resistance in some cowpea cultivars under natural infestation was due to flower thrips infestation escape due to early flowering. Based on these results, it can be deduced that the mechanism of resistance to flower thrips depends on the genotype.…”

“…The lowest damage scores were recorded on the cultivars IT2841*brown, MU20B, WC17, WC29, MU24C, and WC5 (most resistant cultivars); while the highest scores were recorded on WC36 (most susceptible) suggesting some factors conferring the resistance in these cultivars, since resistance to insects can be through their biology, physiology or even their behaviour (Alabi et al, 2004). In fact, cryptic behaviour of some cowpea lines possessing leafy floral structures and growing vigorously could favour gathering of thrips population (Alabi et al, 2003). For instance, cultivars IT2841*Brown and MU20B had smaller racemes and flowers, and probably did not provide enough shelter for thrips compared to the susceptible (WC36) with leafy racemes and flowers.…”

Effect of Native Soap on Insect Pests and Grain Yield of Cowpea (Vigna unguiculata (L) Walp) in Asaba and Abraka during the Late Cropping Season in Delta State, Nigeria

“…The main weapon for management of insect pests on crops all over the years has been the use of synthetic chemical pesticides (Jackai, 1993). However, awareness of environmental pollution, toxicity to mammals, residues in crops and destruction of non-target organisms (Afun et al, 1991;Alabi et al, 2003) due to chemical application has led to their condemnation. Consequently, ecological and integrated pest management (IPM) approach and use of non-conventional chemical that are devoid of the dangers associated with conventional chemicals are presently being explored by farmers.…”

“…pollinators, predators, parasites and parasitoids and ultimately pollute the environment (Alabi et al, 2003). In order to minimise the use of synthetic chemicals, other control measures that are environmentally friendly are presently being advocated.…”