| Opisina arenosella Walker, it is mainly distributed in Sri Lanka and India, and harm the palm plants. At 2013, the pest was first discovered in China, now, in Hainan,Guangdong and Guangxi province have been causing harm to palm plants. This paper mainly studies the adaptability of O.arenosella for 4 host plant, the feeding preference for 4 host plants, and the distribution of this pest on the Cocos nucifera L.. The main findings were as follows:1.The difference about the develop, survive and increase of the O.arenosella, it was reared by host plant leaves of Livistona chinensis, Roystonea regia, Elaeis gunieensis and Cocos nucifera. The results showed: Under the reared of the 4 species host plants, the O.arenosella could have complete the generation, and high survival rate. Breeding by the 4 species host plant,larval stage is differences,and the male larvae duration shorter than female stage; the shortest duration was male larvae , its 35.17±0.54d,by the R.regia leaf reared,and,the Longest was female larval 51.31 ±0.91d by E.gunieensis; The pupa weight,the first was the R.regia reared ,and the second was the L.chinensis, third was the C.nucifera and the E.gunieensis was the light; The pupal stage had a little difference,more than 8 days, but the male pupa was early than female pupae to emergence; The preoviposition period of adults were 1d or 2d, but the fecundity was difference, the most eggs was 236.67±13.63 by L.chinensis, and the least was 160.67±44.03 by R.regia, the egg stage were more than 6d of the 4 host plants; The newly hatch larvae had high death rate of the L.chinensis reared, 5 days late, the survival rate was more than 80% by 4 host plant reared; The highest percentage of female was the L.chinensis reared, up to 63.16%, and more than R.regia 41.48%, the E.gunieensis 52.46% and C.nucifera 53.95%; the increase parameters of experimental population of O.arenosella by the 4 host plants reared, the maximum to minimum of net reproductive rate was the E.gunieensis 42.7852> C.nucifera 36.6251> R.regia 34.0599> L.chinensis 33.133, and the maximum to minimum of the average generationg time was C.nucifera 65.4355d> E.gunieensis 65.0961d> L.chinensis 60.2345d> R.regia 56.8964d; The innate capacity of increase, L.chinensis 0.0581, R.regia 0.062, E.gunieensis 0.0577 and C.nucifera 0.055; The high to low of finite rate of natural increase,R.regia 1.064> L.chinensis 1.0598> E.gunieensis 1.0594> C.nucifera 1.0566.According to the growth reproduction, all suitable for O.arenosella. of the 4 species host plants.2.Through the newly hatched larvae feeding preference for host plant leaves of L.chinensis, R.regia, E.gunieensis and C.nucifera, the leaf feeding and non, and the 4 instar larvae feeding preference for 4 host plants leaf were not fed. The results showed: The newly hatched larvae feeding preference in the no feeding leaf, the highest to lowest was,E.gunieensis 83.89%> C.nucifera 7.88%> L.chinensis 4.7%> R.regia 4.03%; And for the feeding leaf , the newly hatched larvae feeding preference ,the highest to lowest was C.nucifera 30.32%> L.chinensis 29.74%> E.gunieensis 24.45%> R.regia 15.45%. The 4 instar larvae feeding preference for host plant leaf of non feeding, the highest rate was 56%on C.nucifera, next was L.chinensis 22%, R.regia 4%, E.gunieensis 18%. Based on the above resuts of 3 kinds of treatment under the O.arenosella larva feeding preference,discover that the O.arenosella favorite the C.nucifera, next was L.chinensis,R,regia and E.gunieensis, because the newly hatched larva not good to destroy the structure of the leaf,so the newly hatched larva have the highest feeding preference on non feeding of E.gunieensis leaf.3.In order to understanding the damage distribution of O.arenosella in the C.nucifera tree, through field investigation, the resut showed that the mass of larvae and pupae were in the lower leaves, and the fourth leaf layer number of larvae and pupae is most, which accounted for 42.62% and 36.25% of the total; The different leaf layers from top to bottom the harm degree increased, and had know the O.arenosella larvae damage the leaves from top to bottom; The O.arenosella larvae presented pattern of aggregation distribution in the field by aggregated indices; The theoretical and sequential sampling tables of O.arenosella larvae under different population density are established by determining the optimum theoretical sampling formula and sequential sampling formula of O.arenosella larvae according to method of the Iwao. From the survey results, the O.arenosella prefers to feeding mature leaves, and there were mainly distributed in the lower leaves of the three,Investigating the middle and lower leaves of C.nucifera, when have an investigation about the population of O.arenosella. |
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