Raoiella indica

Colmenarez, Y., Moore, D., Polar, P. & Vasquez, C., 2014, Population Trends Of The Red Palm Mite, Raoiella Indica Hirst (Acari: Tenuipalpidae) And Associated Entomopathogenic Fungi In Trinidad, Antigua, St Kitts And Nevis And Dominica, Acarologia 54 (4), pp. 433-442 : 434

Assessment of Raoiella indica populations

An evaluation of RPM population density was conducted in Antigua, St. Kitts and Nevis and Dominica by sampling a total of ten coconut palms per site. A total of 20 palm trees were sampled in Trinidad; ten each at Manzanilla and Icacos. Weather conditions in Antigua, St. Kitts and Nevis and Dominica made it difficult to sample tall plants (<20 feet), therefore sampling was restricted to shorter coconut palm trees.

Samples of pinnae were taken from coconut fronds of various ages. These were classified as young (taking the leaf at approximately 3 months post emergence), medium (approximately 5-6 months post emergence) and old (approximately 7-8 months post emergence). In the case of Trinidad, pinnae were taken from the 3 rd, 5 th and 7 th fronds. Based on previous studies in Trinidad, only the 3 rd and the 5 th frond were taken in the other islands evaluated. Pinnae (5) were cut from the midrib at the base, near the middle and near the tip of the frond. These were placed in labeled plastic bags.

Two pinnae from each bag were randomly selected and cut into three pieces of equal length. The number of live RPM (motile forms) and eggs were counted using a 1 cm 2 cardboard cut-out, at five approximately equidistant points along each segment under stereomicroscope magnification. For Antigua, St. Kitts and Nevis and Dominica, five replications/segment, 15 replications/pinna, 90 replications/frond, and 180 replications/plant were run; giving a total of 1800 replications/area on each island. In the case of Trinidad, 90 replication/frond and 3 fronds/plant were run, resulting in 270 replications/plant and a total of 2700 replications/area.

The means of motile forms and eggs counted on each island were compared using paired t-tests at the 99% level of significance. A square root transformation of the means was required before analysis as the disparity in numbers between islands were highly significant.