ISHS Acta Horticulturae 707: VII International Symposium on Modelling in Fruit Research and Orchard Management
MODELING FROM A CROP PROTECTION DECISION SUPPORT PERSPECTIVE: WHAT IS MOST IMPORTANT? |
| Authors: | J.P. Nyrop, A.N. Lakso |
| Keywords: | integrated pest management, sampling, decision making, critical density, mite, leaf miner, apple |
| Abstract:
A cornerstone of most integrated pest management programs are decision guides that consist of procedures for assessing pest abundance and actions to take based on these assessments. Development of these guidelines depend on two types of models; descriptors of the sampling distribution of pest counts and predictions of the impact of pests on crop yield and quality. Considerable attention has been devoted to the first type of models, while models of pest impact are less well developed. This is problematic because the performance of decision guides depends more on models of pest impact than on models of sampling distributions. We present operating characteristic curves for classifying the abundance of European red mite (ERM) (Panonychus ulmi Koch) and spotted tentiform leafminer (STLM) (Phyllonorycter blancardella Fabricius) to illustrate the importance of the critical pest density, that pest density which signals the need for pest control. We also show that while the impact of ERM and STLM feeding damage on apple leaf photosynthesis is additive and hence amenable to simulation using a carbon balance model, empirical studies were required to describe the unexpected relationship between STLM density and photosynthesis. Furthermore, STLM damage caused increased fruit drop in ‘McIntosh’ trees, a result that could not be predicted by modeling. In general, far greater emphasis needs to be placed on understanding pest damage – crop loss relationships and a combination of empirical studies and simulation modeling should be used in these pursuits. | |
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