Maximum daily temperature, moisture-stress, and atmospheric evaporation proved to be the parameters that accounted for 81-93% of the variation of ECB mortality. Several climatic variables were measured and incorporated into multivariate analyses.

Survival of European corn borer, Ostrinia nubilalis (Hübner) in a single corn field was studied over 2 yr by introducing the insect at ca. The computer approach to this problem does not exhaust all possibilities for assigning numbers, which partially limits the generality of the findings. These advantages include: (1) the use of more powerful, sensitive, better developed and interpretable statistics with known sampling error, (2) the retention of more knowledge about the characteristics of the data, and (3) greater versatility in statistical manipulation (e.g., partial and multiple correlation and regression, analysis of variance and covariance, and most pictorial presentations). The advantages of treating ordinal variables as interval are demonstrated with regard to the relation between occupational prestige and suicide. Errors are determined by the Pearsonian correlation coefficient (r) and r^2. The scoring systems, of which 18 were randomly generated by a computer, resulted in negligible error when comparing any assigned scoring system with any selected 'true' scoring system. Model predictions can be used to time sampling effort in support of management decisions.īy both random and nonrandom assignments of numbers to rank orders (which are consistent with the monotonic nature of the categories), it is shown that ordinal variables can be treated as if they conform to interval scales. 145 degree-days after median pupation, and that numbers of eggs, and first- and second-instar larvae should peak at 200, 310, and 450 degree-days, respectively.

The standard model (tĠ = 10☌) predicts that moth emergence will peak at ca. We conclude that standard thresholds are sufficient for degree-day models for northern populations of O. Use of a standard 10☌ growth threshold to calculate physiological time scales allowed predictions as accurate as those obtained using either a pooled threshold (11.4☌) calculated specifically from Alberta populations, or a model using two thresholds (12.3☌ for fifth-instar larvae to adult and 10.2☌ for eggs to second-instar larvae) that incorporated significant differences in growth characteristics observed among life stages. Predictions from three alternative models were compared against field data from southern Alberta. Starting with overwintered fifth-instar larvae, the model calculates the temporal distribution of first- and second-instar larvae which are the stages most vulnerable to chemical suppression. These host differences in development rate may have been due to the limiting effects of low moisture content in the corn plant tissues employed in the tests.Ī degree-day model was developed for Alberta populations of Ostrinia nubilalis Hübner. Models based on development data using corn as a host ran slow compared with ECB adult emergence on all hosts.

Models based on development data using artificial diet and snap bean pods as hosts closely tracked the actual ECB adult emergence from potatoes and dock, but ran fast when compared with ECB adult emergence from corn. The models were validated by comparison with field cage studies of ECB development on corn, Irish potatoes, and curly dock. These curves were used in predictive models of ECB development. Curves for artificial diet and snap bean pods were similar the curve for corn indicated significantly slower ECB development, especially at higher temperatures. temperature curves were established for each host. In each case, artificial diet, cornstalk sections, and snap bean pods were examined as larval hosts. The development rates of nondiapausing European corn borer (ECB), Oslrinia nubilalis (Hübner) eggs, larvae, and pupae were determined at the following constant temperatures: 15, 18, 20, 25, 30, 32, and 35☌.

Testout lab 10.6