| Meroctena tullalis is one of the most important pests which harm Homaliumhainanense Gagnep,Cotesia ruficrus is the dominant parasitic wasp of the natural regulation of Meroctena tullalis.Here we undertook a detailed study on the morphological characters,determinationof bollworm parasitic characteristics of C.ruficrus and the effects of supplementary exogenous nutrition on the growth of C.ruficru.Moreover,the Mass-rearing technics process was built.The results are as follows:1)Through laboratory determination combined with field investigation,it is found that the three indicators for tell the instar of an individual larva are the head length,the head width and body length.The result showed that with the larvae growing,the body color and the head color became progressively deep.Statistical analysis of the body measurements showed that the head capsule width is the most important as indicators of larval instars,and the natural logarithm of the means of the head capsule width with instar number was significantly correlated(y = 0.1816x ?0.6023 R2 = 0.9991).2)One parasitic enemy of Meroctena tullalis was found for the first time-C.ruficrus.The results shows that C.ruficrus is solitary parasitism.Not only it has high parasitism,but also host-ling is selective.The most preferred host were 3rd instar larvae,whose parasitism and preference index were41.33%and 0.5743.It's body size also increased under the experimental conditions.3)the effect of supplementary exogenous nutrition on the growth of C.ruficrus at room temperature.The results showed that the supplementary foods had significant effects on C.ruficrus' lifespan.The lifespan of the females fed with different supplementary foods were prolonged.The influencing materials were ranked as honey water>sucrose>glucose>fructose>water>nothing.Offspring numbers of C ruficrus fed with honey,sucrose,glucose,fructose and water were 125.7,101.2,94.3,76.1 and 28.9.Longevities of the C.rufcrus fed with different honey concentration,the influencen was ranked as 15%>10%>20%>5%.The lifespan was also significantly extended with the feeding times.With the increase of feeding frequency,the life of the parasitic wasp was obviously different.Parasitoids fed with the sugar solution once per day lived for the longest time.Considering the longevity,and total eggs,feeding frequency and feeding rhythm of C.ruficrus,by 15%honey feeding once a day was the best supplementary food feed,and it could be widely used in the mass rearing of C.ruficrus.4)The mass-rearing and field control effect of results show that with access to host plant 10-15 Meroctena tullalis,you can maximize the use of host plants and get a lot of healthy 3rd instar larvae.When the C.ruficrus was released with the ratio 1:10,it has not only the highest death rate on Meroctena tullalis,but also the number of emergence and emergence rate.Mass rearing process from accessing the host of Meroctena tullalis to collect the adult of C.ruficrus need the 22d.When the C.ruficrus was released with the ratio 1:10 of the parasitoid to whitefly,the control effect reached 67.50%,28.77%and 51.28%after 5,10 and 15 days release.The result show that it prevents the Meroctena tullalis from harming plants. |
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