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REGULAR ARTICLE
The measurement and modelling of losses of cucurbits to Tephritid fruit flies
John M. Stonehouse, Hari S. Singh,
Ravindrakumar K. Patel, Subrata Satpathy, Timalapur M. Shivalingaswamy, Samarjit Rai, Abraham Verghese,
John D. Mumford
Communications in Biometry and Crop Science (2007) 2 (1), 17-25.
ABSTRACT
Losses of cucurbit fruits to Tephritid fruit flies are often assessed
as the infestation percentage of mature fruit at harvest, but this way of appraisal
may underestimate losses, as attacks on pre-mature fruit that are lost before ripening
reduce the mean mass of surviving fruit also. An alternative approach is proposed, which
improves accuracy by incorporating the effects of losses of pre-mature fruit. This approach
entails computation of an aggregate loss by combining infestation levels in four cohorts of
fruit, assuming different rates of compensation by the plant for losses in each cohort.
Using data from different sites in India, this "by cohort, compensated" model obtained
significantly less variability, among replicates of identically-treated plots, than
the mature-fruit-only model, and a pattern of losses comparable to those obtained by
incorporating reductions in surviving-fruit mass. The model is more accurate and realistic
than the assessment of mature fruit only.
Key Words: Cucurbits; fruit flies; economic losses; infestation; compensation; India.
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