Influence of Tillage Systems on Diversity and Abundance of Insect and Nematode Pests of Maize in Malete, Kwara State, Nigeria

Pests are major biotic factors causing up to 45% yield reduction in maize production. There is limited information on pests affecting maize in Malete, Kwara State, Nigeria. The types of insects and nematodes associated with ten quality protein maize varieties (QPMVs) were evaluated for pests’ occurrence, abundance and diversity on ‘plough only plots (POP)’ and ‘plough and harrow plots (PAHP)’ as primary and secondary tillage, respectively.

The experiment was carried out using QPMVs at the Teaching and Research Farm of the Kwara State University, Malete and arranged in a randomised complete block design with 11 treatments replicated 3 times, including local check “pambo”. Data were collected on insect and nematode populations and yield parameters and analysed using ANOVA with descriptive statistics and standard diversity indices at P≤0.05.

A total of 833.1±4.0 and 799.3±3.4 arthropod individuals from POP and PAHP tillage practices, respectively comprising 8 orders and 18 families. Ootheca mutabilis was the most abundant species, with 5.47% (POP) and 5.68% (PAHP) and the least was Rhopalosiphum maidis 1.82% (POP) and 1.80% (PAHP). As indicated by Shannon-Wiener (3.46±0.023) and Simpson indices (0.97±0.0008), there was even distribution in the tillage practices. Three genera of plant parasitic nematodes (PPNs) namely: Meloidogyne spp. [(POP (78.33±19.65), PAHP (1.33±0.33)], Pratylenchus spp. [(POP (41.67±9.26), PAHP (5.00±2.31)], and Helicotylenchus spp. [(POP (58.33±38.35), PAHP (23.33±14.50)] were identified. The yield parameters and a number of the whole plant infested were significantly higher in the PAHP than the POP.

The use of secondary tillage practice is effective in reducing insects and nematodes associated with ten quality protein maize varieties and, therefore, recommended for the management of these pests in maize production.