The Effect of Climate Variability on Agricultural Pest

The impact of climate variability on insect pest occurrence was studied to establish information beneficial to agricultural pest management by monitoring the rates of pest invasion using light trap equipment and ascertain benchmarks of climate changes that influence distribution of the species of brown plant hopper, green leaf hopper, stem borer and parasitic wasp. The research area is within the farmland of Central Luzon State University where climate variables were also observed. Correlation and graphical analysis were used to determine the significant relationship between the two years monthly totals of the pest population samples and the three climatic variables such as temperature, rainfall and relative humidity. Lag of the climate variables up to five months were also included to determine the predictability of the agricultural pests. The result showed no significant correlation between temperature lag four (4) months and brown plant hopper (Figure 1). The green leaf hopper (Figure 2), and stem borer (Figure 3), on the other hand showed significant correlation with temperature lag four (4) months (r2 = 0.7620 and 0.62171, respectively). Unusual result however was obtained between rainfall and relative humidity of the following month with the current monthly population total of parasitic wasp, (Figure 4), with correlation coefficient (r2 ) of 0.72762 and 0.60883, respectively. Based on the facts presented, the following conclusion was drawn: (1) By closely monitoring the temperature variation, agricultural production may be improved by early agricultural intervention knowing that at certain increase in temperature there is a corresponding increase in the population of green leaf hopper and stem borer in four (4) months time; (2) Considering that the two species (green leaf hopper and stem borer) has similar behavior to climate changes, effective pesticides for both species may be developed; (3)The parasitic wasp dynamics maybe used to predict the weather for next month so that dam releases for irrigation may be efficiently scheduled; and (4) The impact of climate variability on insect pests occurrences are good inputs to agricultural pest management to sustain sufficiency in agricultural production; (5) Other disease causing pest to human may be studied in relation to climate variability. Monitoring of the insect dynamics is recommended to be included in agromet observation for future comprehensive study in relation to climate change.