Assessment and comparison of current rodent control techniques towards the protection of young oil palms (Elaies guineensis) in the field

A field study was conducted in the Eastern region of Ghana to assess and compare five methods for the protection of young oil palms (Elaies guineensis) against rodent pests. The rodents attack the bulb of the young oil palm trees leading to eventual death and a reduction in plant stands. The methods (treatments) were broadly grouped into two, with one group comprising two treatments (use of double and single wire nets) recommended by the Oil Palm Research Institute (OPRI), and the other group comprising three traditional methods used by the local farmers (use of basket collars, Jatropha curcus seedlings and regular maintenance schedules). The experiment involved the use of a randomized block design with four replications, each treatment plot consisting of 15 seedlings of oil palm in three rows of five at a spacing of 8.7 metres in a triangular array. Over a twelve-month period, monthly records were taken of the number of dead palm plants and the number of rodent pest attacks as indicated by signs of physical damage to the palm. The results indicated that use of wire nets (OPRI-recommended) was more effective in protecting the young palms against rodent attacks than the “traditional” methods variously employed by local farmers. Economic analysis of the two OPRI-recommended methods, however, indicated that single wire netting (consisting of a single wire collar wound tightly around the basal area of the palm, and placed slightly deeper into the ground to prevent rodents from burrowing through) was more cost-effective than double wire netting, and therefore holds promise for the protection of young oil palms against rodent pests. JOURNAL OF THE GHANA SCIENCE ASSOCIATION Volume 2 No. 2 (2000) pp. 99-10

Preliminary observations of the economic importance of rodents in the establishment of oil palm (Elaeis guineensis) plantations in the Eastern Region of Ghana

Preliminary surveys to assess the damage caused to oil (Elaeis guineensis) seedlings were conducted during the first two years after transplanting to the field. Four oil palm plantations in the Eastern region of Ghana were selected for the surveys in 1996 and 1997. A survey of the suspected rodent pests was also undertaken during the latter part of 1997. The rodents gradually chewed the succulent apical buds of the seedlings, eventually causing the death of the palm. The ultimate objectives of this survey were: (i) to assess the damage caused to the young oil palm plants by rodents; (ii) to develop the capability to identify rodent pests through the recognition of the type of damage they cause to the oil palm, and (iii) to correctly identify the rodent pests of oil palm and to investigate their general biology and ecology for effective control. The damage assessment surveys involved periodic inspections of the plantations, the recording of the number of undamaged seedlings, and calculation of annual percentage seedling losses. The rodent survey involved a capture and identification programme using Sherman collapsible live traps placed along designated transects within the plantations. Identifications were confirmed using identification keys, manuals and voucher specimens. All the rodents captured so far have been identified as Dasymys incomtus (shaggy swamp rat), which has also been observed as a serious pest of oil palm in Nigeria and La Côte d'Ivoire. The assessment of rodent damage in the designated plantations indicated a drastic rise in percentage plant destruction of between 0-3% after the first year, to 41-57% after the second year of transplanting. The need to conduct further research, and the specific areas to be investigated in order to design effective rodent management and control strategies to preserve plant stands for maximum yields, have been stressed. JOURNAL OF THE GHANA SCIENCE ASSOCIATION Volume 2 No. 3 (2000) pp. 164-16