Study On The Adaptability Of Opisina Arenosella Walker To Different Varieties Of Coconut

Opisina arenosella Walker,also known as black-head caterpillar,is one of the most important invasive pestnfor coconut.It was first discovered in Wanning,Hainan in August 2013,and has now been spread to Hainan whole province and some areas of Guangdong and Guangxi province.The larva mainly feed on the old coconut leaves,and builds the path on the back of the leaf,making the leaf dry,causing the coconut fruit production quantity declined,even causing the coconut trees died,which poses a serious threat to the coconut industry in China.The basic research on Opisina arenosella Walker prevention and control in China is still in its infancy,especially the influence of different coconut varieties on the growth and development of Opisina arenosella Walker.On the basis of previous studies,the growth and development of Opisina arenosella Walker on different host plants,the activity of digestive enzyme in the larvae and the content of nutrient and secondary metabolites in the host plant were studied under the laboratory conditions.In order to identify the best host plant,it provides a theoretical basis for the field control,the study of the resistance of coconut ang breeding of the resistant varieties of coconut.The main results are as follows:1.The nutrients of content leaves are different,and the water content is the highest,accounting for more than 50%of the fresh leaf quality.The water content of different host plants and different month is different.The water content in Hainan local Tall is higher than other 4 coconut varieties in the February-April,May-July,Novermber-January of the following year,and the water content of the August-October Yellow Dwarf is the highest.The content of crude fat in Red Dwarf is higher than that of other host plants.The content of crude fat in the leaves of the Novermber-January of the following year is generally higher than that in the other month,and the content of the August-October is lower.The protein content in Hainan local Tall is highest in the February-April,May-July and August-October,and the content of protein in Mawa is highest in Novermber-January of the following year.In the February-April,August-October the reducing sugar of Red Dwarf is significantly higher than that of the other host plants,and the reducing sugar content of May-July generation Yellow Dwarf was higher than that of 4 coconut varieties.The Novermber-January of the following year generation Aromatic coconut had the highest reducing sugar content.The content of soluble sugar in the leaves of Yellow Dwarf in the February-April,May-July generation was the highest,and the soluble sugar content of the August-October in Red dwarf was significantly higher than that of other host plants.The content of Vitamin C in the leaves of the host plant was the highest in the Aromatic coconut.2.The F0 of Opisina arenosella Walker on Red Dwarf has the shortest development period(50.52 + 0.72 d),and the longest development period(64.97 + 1.33 d)on the leaves of Mawa.The F1 of Opisina arenosella Walker has the shortest development period(49.86+0.75D)on Red Dwarf,and the longest development period(62.32 + 0.93d)on the Hainan local Tall.The F2 of Opisina arenosella Walker was the shortest(52.50 + 0.72d)on the Red Dwarf,and the longest(65.34 ± 0.72d)on Mawa.The development of the F3 is the longest(59.29 + 1.23d)on the Red Dwarf,and the longest(70.85 + 1.20d)of the leaves of Mawa.The average development period of the F3 is longer than that of other generations.Opisina arenosella Walker in 5 coconut cultivars except second generations,both from the 5 instar larvae begin to pupate,until 10 instar,mainly concentrated in the age of 7-8,accounted for more than 75%of the overall amount of pupation,and the Opisina arenosella Walker on Red Dwarf pupation were earlier than the other host.And female pupa weight was higher than male pupa weight.3.The food utilization rate,food conversion rate and approximate digestibility of the larvae of Opisina arenosella Walker at different ages in Hainan local Tall are higher than those of other host plants.The difference of food utilization ratio between the 1 instar larvae on 5 coconut varieties is not obvious,the difference of approximate digestibility of the 1 and 4 instar larvae on 5 coconut varieties is not obvious;the larvae of Opisina arenosella Walker at the age of 4,5 and 6 were not significantly different in different host plants.The relative feeding amount of Aromatic coconut at different ages was higher,and the difference in the 2,4 and 5 instar larvae was not significant.4.The digestive enzyme activity of Opisina arenosella Walker,which feeding on different host plants,was different,but the digestive enzyme activity of the same plant was different at the same age in the same plant.Protease activity increased with the growth of coconut moth.The activity of protease in larval larvae was significantly higher than that in young larvae,and the activity of protease in larvae of Red Dwarf was higher than that of other host plants.The activity of amylase,lipase and cellulase in the larva of Opisina arenosella Walker decreased,and the digestive enzyme activity of the larvae was the highest in the low age.The amylase activity of the young and middle age larvae of Opisina arenosella Walker,the high native species of Hainan local Tall,is higher than that on other host plants.The lipase activity of the Opisina arenosella Walker on Hainan local Tall was higher than others.The cellulase activity of the larvae in the F0?F1 generation Mawa and Aromatic coconut was higher than others,and the F2?F3 generation of Hainan local Tall was higher than others.5.The growth and development of Opisina arenosella Walker on Red Dwarf and Aromatic coconut were positively correlated with the total nutrient content in the coconut leaves,the intestinal digestive enzyme activity in the middle intestine was higher,and the other 3 varieties were negatively correlated,and the negative correlation on the leaves of Mawa was the strongest.Therefore,Wen Red Dwarf and Aromatic coconut are more beneficial to the breeding of Opisina arenosella Walker than other coconut varieties,and Mawa is less beneficial to the breeding of Opisina arenosella Walker than the other 4 coconut varieties.