Relationships among rat numbers,abundance of oil palm fruit and damage levels to fruit in an oil palm plantation

The relationships between vertebrate pests and crop damage are often complex and difficult to study.In palm oil plantations rodents remain the major pests,causing substantial monetary losses.The present study examined the numerical and functional responses of rodents to changes in the availability of oil palm fruit and the damage associated with that response.For the study,200 traps were set in pairs on a 10×10 trapping grid for 3 consecutive nights in each of 6 study plots at 8-week intervals in a 2569 ha oil palm plantation at Labu,Negeri Sembilan state in Peninsular Malaysia over 14 months.A total of 1292 individual rats were captured over 25200 trap-nights.Animals were identified,aged,sexed,weighed and measured.An index of the relative abundance of rats was calculated based on trapping success.Damage to infructescences was assessed at each trap point.Regardless of the age of palms,there were positive and significant relationships between the relative abundance of rats and numbers of infructescences.The levels of damage to infructescences were significantly correlated with the relative abundance of rats.A steep increase in damage was observed with an increase in mature infructescences,indicating a feeding preference of rats for mature infructescences.For both males and females of all rat species,there were weak and non-significant correlations between body condition and infructescence numbers.These results indicated that there was a numerical and a functional response by rats to the availability of palm fruit and a resulting increase in depredation of oil palm fruits.The ways in which this information might aid in future pest control are discussed.

Evaluation of an ＂Attract and Kill＂ System to Combat Ceratitis capitata on Peach Trees in Tunisia

Attract and kill （AK） technology was evaluated against the Mediterranean fruit fly （Med-fly）, Ceratitis capitata W.. Treatment was carried out in two peach orchards of four hectares each; first one located in Borj-Touil and the second in El-Kssibi Mornag, Northern Tunisia during the 2012 field season. AK is a specialized system based on hydrolyzed proteins and alpha-cypermethrin. During this study, 400 AK bait stations were placed in every hectare, four weeks before fruits color changes. The tested AK system was found effective in reducing the number of C. capitata population to 70% comparing to the untreated orchards. Fruit damages assessment showed significant differences between treatments in respect of decreasing infestation onto fruits Study results indicated that AK baited treatments were able to reduce dropped and soften fruits infestation seven times than that of control plots. Fruit damages were restricted to 4%-5% in treated areas with AK system in compare to 31%-35% recorded in control plots. This novel AK system showed good performance to combat Med-fly and can successfully used to combat various fruit fly species when applied for an area wide application program.