 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Species Diversity of Cotton Insect Pests) ผู้เขียน: Ohnmar Khaing,  ดร.ประภารัจ หอมจันทน์, ศาสตราจารย์ , นายสุรเชษฐ จามรมาน, รองศาสตราจารย์ , Ngarmchuen Ratanadilok, นางอรุณี วงศ์ปิยะสถิตย์, ศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractField experiments were conducted at Suwan Farm, Northeastern Thailand during two growing periods of 2000 and 2001 to determine the species diversity and abundance of insect pests of cotton. Randomized Complete Block Design (RCB) was arranged with four replications of sixteen plots of four cotton varieties/lines. Weekly sampling was performed by visual count and pan trap methods. Species diversity of insect pests was analyzed by Shannon-Weaver diversity index. Species abundance of insect pests was computed for each crop together with eight sampling dates. Species ranking was also developed from species abundance. The results showed that insect pests were greatly abundant during the first crop while low diversity indices were observed. During the second crop there was less appearance of insect pest. The total species abundance of all varieties/lines ranged from 10 (cotton spiny bollworm, Earias sp.), to 11,431 (cotton leafhopper, Amrasca biguttula Ishida), in the first crop and from 11 (Earias sp.), to 1,955 (A. biguttula), in the second crop. The ranges of species diversity indices were from 0.27 [Sri Samrong 60 (SR 60)] to 0.62 [Sarid 1 (SD1)], in the first crop and from 0.61 (SR 60) to 0.83 (SD1), in the second crop. A. biguttula was observed to be the dominant species in both crops. Other insect pests with less obvious importance were Thrips palmi, Bemisia tabaci, Aphis gossypi, Megacoelum biseratense and Carpophilus sp. Although total of 28 species found on cotton, only 13-14 insect pests appeared in the cotton field regularly. Two rare species did not occur on some cotton varieties/lines during the second crop. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Spatial Dispersion and Optimum Sample Size for Cotton Bollworm, Helicoverpa armigera (H?bner) (Lepidoptera: Noctuidae) Larvae on Cotton) ผู้เขียน:Ohnmar Khaing, ดร.ประภารัจ หอมจันทน์, ศาสตราจารย์, Surachrat Jamornmarn, Ngarmchuen Ratanadilok, นางอรุณี วงศ์ปิยะสถิตย์, ศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractField experiments were conducted in the irrigated and the rain-fed crops of 2000 and 2001 at Suwan Farm, Pak Chong, Nakon Ratchasima, Northeastern Thailand to determine the spatial dispersion of cotton bollworm, Helicoverpa armigera (H?bner) larvae on four cotton varieties/lines, namely, AP1 and AP2, the mutant lines, SR60 (Sri Samrong 60) and SD1 (Sarid1), the recommended varieties. RCB was used with four replicates for both crops. The spatial dispersion was analyzed using the variance-to-mean ratio (s2/ x), Morisita’s Index (I?) and the negative binomial parameter (k). Although cotton bollworm larvae exhibited mainly clumped distribution, sometimes it was found to be randomly disperse during the sampling periods of both crops. In general, H. armigera larvae were at high aggregation (k=0.10) on the irrigated crop and low aggregation (k=3.92) on the rain-fed crop. The dispersion information was used to select an optimum sample size at the 0.05 probability. The optimum sample size of 15 and 30 plants per 140 m2 were needed to monitor low and high aggregation levels of H. armigera larvae, respectively. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Spatial Distribution Pattern of Cotton Leafhopper, Amrasca biguttula (Ishida) (Homoptera: Cicadellidae)) ผู้เขียน:Ohnmar Khaing, ดร.ประภารัจ หอมจันทน์, ศาสตราจารย์, นายสุรเชษฐ จามรมาน, รองศาสตราจารย์, Ngarmchuen Ratanadilok, นางอรุณี วงศ์ปิยะสถิตย์, ศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractThe spatial distribution pattern of cotton leafhopper, Amrasca biguttula (Ishida) was studied under field conditions during 2000 and 2001 at Suwan Farm, Pak Chong, Nakon Ratchasima, Northeastern Thailand. The cotton varieties/lines: Sri Samrong 60 (the recommended variety), Sarid1 and new mutant lines AP1 and AP2 were used in the experiments employing Randomized Complete Block design with 4 replications. The results of both seasons showed that the distribution of A. biguttula was clumped for all varieties/lines and degree of aggregation considerably changed during the generations, as indicated by the values of variance to mean ratio (s2/ x), negative binomial parameter (k) and the index of aggregation (I?). The results of distribution analysis were used to estimate a given sample size and precision level of cotton leafhopper. The appropriate sample size of maximum 10 and 30 plants could be required at low and high aggregation levels of A. biguttula, respectively. |