Citrus is a banner commodity of Nueva Vizcaya State University and Cagayan Valley (Region 2). The greatest volume of mandarin production comes from Kasibu, Nueva Vizcaya and the production is declining partly attributed to pests and diseases specifically aphid and rind borer insects. This study aimed to model the incidence of aphids (Toxoptera citricidus) and rind borers (Prays endolemma Diakonoff) using the different weather elements in Kasibu, Nueva Vizcaya specifically temperature, rainfall, humidity, and solar radiation. Time Series Analysis using expert modeler was used to generate weather models and NCSS was used to forecast weather values. Multiple Linear Regression Analysis was also used to generate the prediction model of the incidence of aphids and rind borer. The temperature model is ARIMA (0,1,9), rainfall model is ARIMA (0,0,0), humidity model is ARIMA (1,1,0), and solar radiation model is ARIMA (3,1,0). It was found out that Temperature 1, Temperature 2, and Rainfall 2 have significant correlation with the population of aphids, and weather elements have no significant correlation with the population of rind borers resulting to no generation of rind borer prediction model. it was also found out that the best predictor of the incidence of aphids are temperature 2 and rainfall 2. This study recommends that the timing for the pest control measures for aphids should be administered two weeks before the population could increase.

Keywords: Cirus, Aphids, Rind Borers, Weather Elements, Modeling, ARIMA, Time Series Analysis, Multiple Linear Regression Analysis

Thesis (Master of Science Teaching - Mathematics)

Includes appendix and bibliographical references.