| The coconut black-headed caterpillar, Opisina arenosella Walker, newly discovered in Wanning, Hainan in China in August,2013, is a kind of leaf eating invasive pests in coconut trees. The pest mainly infected the coconut leaves by the larvae. The caterpillars weave silken roads with silks and frasses in the back of the leaves, leading to the dryness of the leaves and even the dieback of all the canopy of the trees. The caterpillar is a dangerous harmful organism of forestry which makes the plantation of the palm like the coconut in Hainan face serious threats. So far, the biological and ecological research about the pest at home and abroad has been described, but no detailed study has been conducted. There is also less report about the chemical control of the pest. In this paper, on the basis of previous studies, further biological and ecological characteristics of coconut wood moth, simple pesticides screening indoor to the pest were studied. The main results are as follows:1. Through the indoor rearing and field investigation, the behavior habits of the egg, larva, pupa and adult and other insect morphology of the coconut black-headed caterpillar were observed and described in details, including the egg hatching, larval feeding, activity, molting, pupation, eclosion, mating, oviposition behavior of adult. The caterpillars like laying their eggs in the tunnels of the larvae. The eggs incubation commomly needs5-7d. The larvae gathered feeding at the beginning and then dispersed. The feign death, the silking and droping and the dog-eat-dog phenomenons were found. Pupation generally happened in the tunnels. The color of pupal changed from reddish to reddish-brown. The eclosion peaks appeared between17:30and19:30. And the same day the adults can just mate. The mating time was between23:00and6:00and the mating peak appeared between0:00and2:00. Mating can last from30min to1h.2. This study was conducted to determine the larval instars of the coconut black-headed caterpillar by the head-capsules collection both from the field and the laboratory rearing. The head-capsule widths obtained from the experiment were then analyzed using the frequency distribution and the linear regression. The Dyar rule and the Crosby rule were used to validate the rationality of the division. The results were that the caterpillar can be divided into5instars in the field and5-8instars in the laboratory conditions. Compared with the result in the field, the instars of the larvae in the lab increase. The reason is probably that the environmental conditions in the lab like the temperature, the moisture, the photoperiod, the food and the population density, heredity in the lab are different from the field, the conditions in the lab are not good enough to maintain the development like in the field.3. The adult longevity, fecundity, the developing time and the survival of immature stages of O. Arenosella at7constant temperatures from16?to40?were studied. The mean fecundity per female at16,20,24,28,32,36,40?was46.8±13.7,44.2±9.6,141.3±13.7,120.3±17.0,104.5±10.6,81.6±13.1,10.3±7.0eggs, respectively. The mean preoviposition period ranged from1.5days at36?to5.9days at20?. Only eggs from24?to36?can incubate. The oviposition period ranged from2.6days at36?to7.6days at24?. Only from24?to32?the caterpillars can complete their lifecycle. The development time decreased with the increase of the temperature. The mean development time (mean±SE) ranged from88.0±1.4days at24?to57.7±3.1days at32?for total generation, respectively. The developmental zero for egg, larval, pupa and total development is19.7±1.2,17.9±3.1,12.9±4.2and12.7±2.4?, respectively. The thermal constant for egg, larval, pupa and total development is45.0±6.7,454.4±125.4,151.2±51.9,1015.4±152.4DD (degree-days), respectively. The most suitable developmental temperature is between24?and28?. |
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