Table 6.

Univariate linear regression models of goji psyllids and goji gall mites with respect to disease index.

Types of Diseases and Pests	Simulation Equation	R2	Sig.
goji psyllids	DI = 10.119 − 1264.591 × first-order derivative of R700	0.986	0.001
	DI = 13.587 − 520.533 × SDb	0.967	0.003
	DI = 8.264 + 1496.754 × SDg	0.827	0.016
goji gall mites	DI = 5.732 − 474.858 × first-order derivative of R700	0.983	0.001
	DI = 5.959 − 173.345 × SDb	0.98	0.001
	DI = 6.072 − 155.721 × SDg	0.972	0.002

A higher R² coefficient, closer to 1, indicates better model fit; a smaller standard error (Sig.) value indicates better regression performance. According to Table 5, the regression models using the first-order derivative of R₇₀₀ as variables proved to be the best for both goji psyllids and goji gall mites.