Stenoma impressella is one of the most important defoliator pests in oil palm plantations in Colombia. To identify an alternative method for its control was characterized biologically and molecularly two strains of Cordyceps cateniannulata (CPIsp1201 and IPIsp1201) and three strains of Beauveria bassiana (CPBb0502; CPBb0411; CPBb0404) against S. impressella larvae. Virulence was evaluated under laboratory conditions. In an oil palm leaflet, individual larvae obtained from the insect colony were inoculated with 5 μl of a conidial suspension containing 1 × 10 7 conidia/ml. The five strains were pathogenic against S. impressella larvae. CPIsp1201 and IPIsp1201 strains resulted in the highest mortality and were subsequently evaluated in two bioassays using a dose of 1 × 10 13 conidia/ha. In the first bioassay, performed under shaded conditions, leaves of oil palms were infested with 75 larvae from the breeding/treatment. The second bioassay was performed in the field using natural populations. No differences were found between strains in both bioassays and the different dosages (5 × 10 12 , 1 × 10 13 , and 1.5 × 10 13 conidia/ha). Finally, the two strains were evaluated under oil palm plantation conditions at a dose of 1 × 10 13 conidia/ha in 126 naturally infested palms. Larval mortality caused by the strains IPIsp1201 and CPIsp1201 (79.5% and 70.5%, respectively) was higher than the natural mortality registered in the control (37.3%). Cordyceps cateniannulata used at 1 × 10 13 conidia/ ha was effective at controlling S. impressella.

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Rhynchophorus palmarum (L.) (Coleoptera: Dryophthoridae) is an important pest in oil palm plantations, and its populations are monitored through rhynchophorol pheromone-baited traps. To optimize the release of rhynchophorol in high-density polyethylene diffusers, five calibers (2, 3, 4, 5, and 6) were evaluated. The experiment was conducted under a completely randomized design with 15 repetitions, recording daily weight loss of pheromones. Release rate of pheromone under laboratory conditions (30.2 ± 0.1°C; 70.8 ± 0.8% relative humidity [RH]) varied between 2.2 and 10.4 mg/day. Three diffusers with 2.4 ± 0.4, 3.6 ± 0.9, and 8.5 ± 1.3 mg/day of release rates, were selected for testing in three palm-growing zones. Adults of R. palmarum captured in traps with different diffusers were counted as well as pheromone weight loss. In two of three plantations, statistical differences were found in the capture of R. palmarum adults among the diffusers that presented different pheromone release rates (Eastern: F = 8.27; df = 2, 9; P = 0.0028; Central: F = 10.79; df = 2, 9; P = 0.0008; Southwestern F= 2.20; df = 2, 9; P= 0.1402). The diffuser with the release rate of 2.4 mg/day was selected because, after remaining 4 mo in the field, the traps with this diffuser registered catches statistically equal to those that had traps with newly installed diffusers. We concluded that the release rate of the pheromone of 2.4 mg/day is optimal for the capture of adults of R. palmarum during a period of 4 mo.

The adults of Strategus aloeus (L.) feed on the bulb and cause damage to young oil palm that can lead to lesions, and ultimately, to rotting. The aim of this study was to determine the S. aloeus damage in young hybrid oil palms, to propose an alternative method for its monitoring and control. Initially, destructive samplings of the palms were made at 8, 10, 12 and 15 days after insect attack. Additionally, weekly insect attack monitoring and rainfall register were made. About 44.4% of the oil palms were damaged after eight days of the adult's infestation. During the first year of the crop's establishment, there was a positive correlation between the number of galleries and rainfall. During the second and third year, there was a negative correlation between the number of galleries and oil palm age (ρ=−0.93; p<0.0001; n=105). Our study found that the damage caused by S. aloeus in hybrid cultivars can be observed eight days after the adult´s arrival. The monitoring and control of S. aloeus in hybrid cultivars should be performed on a weekly basis from establishment to the first three and a half years of the crop.