author(s)
Kari Iamba and Veronica Homband

abstract
The public is now more aware of the negative impacts of synthetic pesticides to the natural enemies, beneficial insects, general human health and development of pest resistance. In this study, two (2) repellent plants, Marigold flower (Tagetes erecta L.) and Onion (Allium cepa L.) were intercropped with Pak choi (Brassica rapa chinensis) in an attempt to lower pest abundance and damage to foliar. Separation of treatment means by Tukey HSD test showed that marigold intercrop (p<0.05) was effective in lowering the population of two common cabbage pests, Plutella xylostella and Psylliodes chrysocephala. Onion intercrop and control treatment (sole Pak choi) did not show any significant differences in the response variables: (1) pest abundance, (2) defoliation (%) and (3) leaf area index (LAI) (p>0.05). Both temperature (°C) and relative humidity (%) are critical abiotic factors that determines the activity of natural enemies as well as pests. There was a positive correlation between temperature and LAI in control treatment (r=0.33, p<0.05), onion intercrop (r= 0.23, p<0.05) and marigold intercrop (r= 0.25, p<0.05). A negative correlation existed between relative humidity (%) and pest abundance (r= 0.18). These relationships contributed to variations in the response variables.