The coconut mite, Aceria guerreronis (Acari: Eriophyidae) and the coconut moth, Atheloca subrufella (Lepidoptera: Phycitidae), exploit the same habitat—meristematic region underneath the coconut fruit perianth. The coconut fruit perianth, however, is a tight structure allowing free colonisation of the meristematic region of the fruit only by small arthropods such as the eriophyid and tarsonemid mites. Fruits infested by the mites develop different levels of necrosis around the perianth providing access to colonising larvae of the coconut moth, which bore the fruit under the perianth resulting in fruit abortion. Based on field observations, we hypothesise that A. subrufella will colonise coconut fruits only if they exhibit damage on the perianth such as the necrosis caused by the coconut mite. Fruits with and without necrosis were collected from different production areas located in three different states along the Brazilian Atlantic coast and inspected for infestation with coconut moth larvae. In the laboratory, coconut fruits with and without necrosis were offered to moths for oviposition preference and tested for colonisation by neonate and third instar larvae. The results showed that the moths showed no preference for fruits with or without necrosis for oviposition and, hence, neonate larvae have to go under the perianth bract to reach the meristematic region of the fruit. However, neonate larvae were unable to colonise fruits without necrosis (0%) compared to 23% and 60% of fruit colonisation success when exhibiting mite necrosis or mechanical damage, respectively. Similar results were found with respect to older coconut moth larvae. Thus, the data support the hypothesis that the indirect interaction through previous fruit colonisation and necrosis caused by the coconut mite allows the larvae of A. subrufella to be a key pest of coconut fruits.
Rearing Technique and Biological Traits of Atheloca subrufella (Hulst) (Lepidoptera: Phyci dae) in Coconut Fruits.Larvae of the coconut moth Atheloca subrufella (Hulst) develop in lowers and fruits of coconut, Cocos nucifera, causing precocious abscission of these structures and, hence, yield decrease. This work studied a feasible and suitable rearing technique for A. subrufella using fruits of coconut. We irst determined the appropriate density of larvae to be reared per coconut fruit (among two, three, four or ive larvae) and later tested the suitability of this rearing technique for three successive generations. The storage of egg and pupal stages during 0, 5, 10 and 20 days was also studied at 12 o C. Based on the fertility life table parameters, the best results were achieved by rearing two or three larvae per fruit as they yielded the best net reproductive rate and intrinsic rate of population increase. In addition, eggs and pupae of A. subrufella can be stored at 12 o C up to ive days with viability higher than 90%. Adult moths emerged from pupae stored for ive days at 12 o C produced an average of 219.4 eggs and lived 18.8 days. Storage periods for eggs and pupae over 10 days signi icantly reduced egg viability and adult fecundity, respectively. Thus, the technique in here described was shown to be suitable for the continuous rearing of A. subrufella in laboratory conditions.
-Among the important pests of coconut, the coconut moth Atheloca subrufella (Hulst) is a signifi cant pest of fl owers and fruits, and is found across all coconut-producing regions in Brazil. We investigated the thermal requirements of A. subrufella and estimated the number of generations for two different growing coconut regions in Pernambuco State. The developmental time of all immature stages reduced as the temperature increased. The egg to adult period ranged from 19.3 to 59.8 days from 32ºC to 18 o C, respectively. The survival of the period from egg to adult was 25% at extreme temperatures (18 o C and 32 o C), while at the intermediate temperatures it was over 72%. Based on the thermal requirements determined for A. subrufella and the average temperatures determined for "Zona da Mata" and "Sertão" of Pernambuco State, it was estimated that A. subrufella is able to complete up to 13 generations per year in both areas. These results indicate that A. subrufella exhibited development and reproduction limited by temperatures higher than 32 o C and lower than 18 o C. However, based on the thermal requirements of A. subrufella and the mean temperatures of the "Zona da Mata" and "Sertão" of Pernambuco State, this pest can develop throughout the entire year.
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