Kanitta Pankeaw, Aran Ngampongsai, Surakrai Permkam, and Onkamol Rukadee

pp. 263 - 269

Abstract

We investigated the abundance and distribution of thrips in a farmer’s mangosteen orchard by comparing single- and
mixed-cropping systems at Nakhon Sri Thammarat province, the main planting area in southern Thailand, between April
2005 and January 2006. A monitoring program at two-week-intervals was done to measure the number of thrips by using
twenty yellow sticky traps per each cropping system. The mean number (223.5±23.4 thrips/trap) of thrips throughout the
period of study in the monocrop mangosteen sites was significantly (P<0.01) higher than 69.1±8.3 thrips/trap in the mixedcrop mangosteen sites. Scarring on the fruit surfaces damaged by thrips was visually quantified, with average percentages of
scarring 32.2% and 19.8% in the mono- and mixed-cropping systems, respectively. Distribution of thrips in the upper and
lower halves of the plant canopy in the four cardinal directions was studied by assessing scarring on the fruit surfaces. The
percentage of scarring occurring in the upper canopy was significantly (P<0.01) higher than in the lower canopy. In the
single-crop system, the average percentages of scarring were 46.6% and 25.4% on the upper and lower canopies, respectively.
In the mixed-cropping system results obtained were similar to those in the single cropping system, with 31.5% and 20.4% on
the upper and lower canopies, respectively. The severity of damage to the fruits caused by thrips seemed to be higher in the
North and East directions than in the South and West. In conclusion, mixed-cropping mangosteen orchards are recommended
for reducing fruit damage caused by thrips. Fruits occurring on the upper canopy, in the North and East sides, should be
underlined for thrip control to meet the criteria for high quality mangosteen production from the south of Thailand.