Effects of two pheromone trap densities against banana weevil, Cosmopolites sordidus, populations and their impact on plant damage in Uganda

Abstract

An on-farm study to evaluate the effect of pheromone trap density on the population of the banana weevil, Cosmopolites sordidus (Germar) (Col., Curculionidae) was conducted in Masaka district, Uganda. The pheromone used was Cosmolure+, a commercially available weevil aggregation pheromone. Forty-two farms were assigned to one of three treatments: 0, 4 and 8 pheromone traps/ha. Pheromone lures were changed monthly at which time the traps were moved to a different location within the stand. Adult weevil population densities were estimated by using mark and recapture methodology at 0, 6, 12, 18 and 21 months, while damage to the banana corm was assessed at 0, 3, 6, 12, 18 and 21 months since the start of the experiment. Pheromone trap captures were generally low: about 10 weevils per trap per month. There were no significant differences in mean catches of C. sordidus per trap per month except for February 2002 when doubling the pheromone trap density decreased weevil catches. Although not significant, decreased efficiency was also the trend in higher trap densities over all the data sets. Doubling the number of traps increased the number of weevils caught per hectare per month from 0.4 to 0.6%. There was no significant difference in plant damage between the pheromone treatments in low-compared with high-trap densities. There were generally no significant differences in weevil populations and plant damage between pheromone-treated and control farms. Possible reasons for the low-trap efficacy in this study are discussed.

Visual Cues Are Relevant in Behavioral Control Measures for Cosmopolites sordidus (Coleoptera: Curculionidae)

“…Cosmolure sealed in a white polymer-membrane release device and optimized for C. sordidus (ChemTica Internacional S.A., San José , Costa Rica). The lure packs, each containing 90 mg of pheromone appearing in blue and with a release rate of 3 mg/d (Tinzaara et al 2005) were stored at 4ЊC until use. Lures were hung on 2-cm copper wires suspended from the top of each ground trap.…”

Use of aggregation pheromone traps increases infestation of adult Riptortus pedestris (Hemiptera: Alydidae) in soybean fields

“…Even though Leskey et al . and Tomasev et al . found higher trap catches in high‐density trapping plots than in low‐density trapping plots, they did not find any reduction in infestation in either high‐ or low‐density trapping plots.…”

Management of Cosmopolites sordidus and Metamasius hemipterus in Banana by Pheromone-Based Mass Trapping

“…Pheromone trapping trials on small holder plots reveals that at four traps/hectare (or even at eight traps/hectare as examined in one study) that reduction of C. sordidus capture rates and corm damage are often not significantly reduced (Tinzaara, et al, 2005). Failure of this trapping system in small holder plots could be due to less consistent management tactics or to immigration from surrounding areas, or both.…”