The accuracy and bias of visual assessments of fruit infestation by fruitflies (Diptera: tephritidae)
Abstract
The attacks of fruitflies are conveniently assessed by visual inspection of fruit. This study assessed the accuracy of this in Pakistan by recording visual diagnoses of attack on individual fruit and waiting to see if these were 鈥渃onfirmed鈥� by subsequent emergence of prepupal larvae. Diagnoses as 鈥渦nattacked鈥� were overwhelmingly 鈥渃onfirmed鈥�; diagnoses as 鈥渁ttacked鈥�, by oviposition punctures, were 鈥渃onfirmed鈥� by larval emergence in 56% of cases in melons, 39% in guavas, 40% in jujubes and 27% in mangoes. The fact that diagnoses as 鈥渦nattacked鈥� were 鈥渃onfirmed鈥� more often than as 鈥渁ttacked鈥� suggests that the discrepancy may not be in misdiagnosis but in larval mortality, and that visually recorded scars which led to no larval emergence were indications of eggs or larvae dying before maturity: this possibility has little economic significance, however, as larval survival and emergence, not oviposition, are the cause of losses to the farmer.
Citation
Stonehouse, J.M.; Mumford, J.; Poswal, A.; Mahmood, R.; Hamid-Makhdum, A.; Mahmood-Chaudhary, Z.; Nawaz-Baloch, K.; Mustafa, G.; McAllister, M. The accuracy and bias of visual assessments of fruit infestation by fruit flies (Diptera: tephritidae). Crop Protection (2004) 23 (4) 293-296. [DOI: 10.1016/j.cropro.2003.08.014]