Pandan leaf is a tropical plant that is commonly used as a flavoring agent in Southeast Asian cuisine. There is some anecdotal evidence that suggests that the aroma of pandan leaf can repel cockroaches, but there is limited scientific evidence to support this claim.
One study published in the Journal of Vector Ecology in 2005 investigated the effects of pandan leaf extract on German cockroaches. The researchers found that the extract had some repellent effects, but the concentration needed to achieve a significant effect was much higher than the typical concentration used in cooking.
Another study published in the International Journal of Tropical Insect Science in 2019 investigated the effects of pandan leaf oil on the behavior of German cockroaches. The researchers found that the oil had some repellent effects, but again, the concentration needed to achieve a significant effect was much higher than the typical concentration used in cooking.
Overall, while there is some evidence that pandan leaf may have some repellent effects on cockroaches, more research is needed to confirm its efficacy and determine the optimal concentration and method of application. Additionally, other methods such as proper sanitation and the use of insecticides may be more effective for controlling cockroach infestations.
The use of pandan leaf to ward off cockroaches is a commonplace tradition, but as to how effective it is remains to be seen (or smelt!)
