Impact of different pineapple mealybug densities in a peanut crop

Resumen

The pineapple mealybug Dysmicoccus brevipes (Hemiptera: Pseudococcidae) is a cosmopolitan and polyphagous species that causes severe damage to peanut crops in many countries around the world. This work was conducted in Campina Grande, Paraíba Sate, Brazil, aiming to assess losses in productivity caused by D. brevipes in a peanut crop. A completely randomized design with five treatments and four replicates was used. Treatments consisted of five mealybug population densities (nymphs and adults) on peanut roots and pods, described as follows: T₁ = 0 mealybugs per plant; T₂ = 1 to 20 mealybugs per plant; T₃ = 21 to 40 mealybugs per plant; T₄ = 41 to 80 mealybugs per plant and T₅ = more than 80 mealybugs per plant. Roots and pods infested with the pest were observed on 84 % of the peanut plants sampled, ranging from zero to 147.1 individuals per plant. The higher the number of mealybugs per plant, the lower the weight of pod. The mean pod productivities of BR1 peanut cultivars, with the highest and lowest densities of mealybugs per plant were 1,695 and 3,290 kg per ha, respectively. Fields heavily infested with D. brevipes risk significant losses due to the enormous capacity of this organism for causing damage.