Determination of damage caused by different populations of Diloboderus abderus (Coleoptera: Scarabaeidae) larvae on wheat

Abstract

Wheat (Triticum aestivum L.) is the most widely cultivated cereal crop worldwide because it is an important food source for humans. South America has long been associated with wheat production and export. Given the increased application of no till in the last decades, the scarabid Diloboderus abderus has become the main soil pest of this crop. The larvae of this insect (white grubs) feed on roots, causing plant weakening and death. The aim of this work was to determine the relationship between the soil population of D. abderus larvae and the number of established wheat plants. In a plot cultivated with the wheat cultivar Don Mario Algarrobo at a seeding rate of 130 kg ha-1 and with high population levels of this pest, 1-m2 sites with 20-39; 40-60; 80-100; 120-160 and or 200-240 plants were established. At the tillering phenological stage, the number of tillers per plant and of insect larvae in each subplot was counted. The results showed a significant reduction in plant density with increasing soil larval population. The crop counterbalanced the reduction in plant number by increasing the tiller number per unit area. The present work shows that population levels above 11 larvae m-2 generate a significant reduction in the number of wheat plants established in the crop.