WAEC Agricultural Science Past Questions & Answers - Page 8

The cotton stainer is an insect pest of cotton plants. The cotton stainer is an insect pest that primarily affects cotton plants, causing damage to the seeds and leading to staining of the cotton fibers, impacting cotton yield and fiber quality.

Thinning refers to the process of reducing the number of seedlings in a plant stand to achieve proper spacing and optimum plant density. In the context of the question, thinning involves removing one out of three seedlings of maize, resulting in two plants remaining per stand.

All the tools listed are used in soil analysis. A pH meter is used to measure the acidity or alkalinity of the soil. A sieve is used to separate and grade soil and rock particles according to their size. A hygrometer is used to measure the moisture content in the atmosphere, which can affect soil moisture levels.

Cover crops are plants that are primarily grown for the benefit of the soil rather than the crop yield. They are typically grown to suppress weeds, manage soil erosion, help build and improve soil fertility and quality, and control diseases and pests. Centrosema pubescens and Mucuna utilis are examples of cover crops. They are used to improve soil fertility and control weeds.

High humidity in a brooder house creates a conducive environment for the growth and multiplication of pests and diseases. It can also lead to the development of mould and fungi, which can be harmful to the chicks.