Abundance and Population Dynamics of the Key Insect Pests and Agronomic Traits of Tomato (Solanum lycopersicon L.) Varieties under Different Planting Densities as a Sustainable Pest Control Method

Abstract

In Saudi Arabia, the tomato is susceptible to a wide range of insect pests that could destroy this valuable vegetable crop, cause yield losses, and affect fruit quality and quantity. Insecticides are widely applied to protect tomatoes and control pests that develop a resistance to pesticides, but these affect human health and have a negative impact on the environment. The application of Good Agriculture Practices (GAP) is a worthwhile sustainable alternative for controlling insect pests in tomato fields. To investigate the population dynamics of the major pests affecting tomato growth and yield, two commercial varieties (Areenez F1 and Tala F1) were cultivated at three plant spacings (30 × 50 cm, 60 × 50 cm, and 90 × 50 cm) under the conditions of the desert climate. The experiments were conducted in the field in 2020 and 2021 and were laid out in a Randomized Complete Block Design (RCBD) with each treatment repeated for 4 times. A total of 14 major insect pests including Empoasca fabae, Bemisia tabaci, Orosius orientalis, Acheta domesticus, and Lasius niger were recorded on a weekly basis. The results showed that the mean abundances of E. fabae, O. orientalis, and B. tabaci were higher in the 30 × 50 cm plant spacing, whereas the 90 × 50 cm plant spacing resulted in a higher abundance of A. domesticus and L. niger. The measured agronomic traits, plant height (cm), plant dry mass (g), and total yield/ha (ton) of both the tomato varieties were significantly increased when the plants were spaced at 60 cm between plants and 50 cm between rows. We recommend that growing tomato plants at 60 cm between plants and 50 cm between rows may reduce the need to apply pesticides given that this plant spacing significantly reduced the abundance of some key insect pests and enhanced the tomato fruit yield.