Snails (kuhol) are controlled with neem, tubli, makabuhay and other plants.

Dr Abe V Rotor 

Living with Nature School on Blog

Paaralang Bayan sa Himpapawid (People's School-on-Air) with Ms Melly C Tenorio
738 DZRB AM Band, 8 to 9 evening class Monday to Friday

Golden Kuhol (Pomacea caniculata) is the number one 
pest of rice today in the Philippines 

Pomacea is a genus of freshwater snails with gills and an operculum, aquatic gastropod mollusks in the family Ampullariidae. As Pomacea it is commonly sold in the aquarium trade as "[color] mystery snail" in the United States. Wikipedia

Before the introduction of chemical pesticides our native kuhol was a good source of viand in the ricefield and seldom did it turn against growing rice plants. Almost simultaneously in the sixties the golden kuhol or apple snail (Pomacea caniculata) was introduced with the promise that it is a better gourmet, and that it could even be exported.  It did not turn out that way, and with the resistance this exotic mollusk developed having left behind its natural enemies, it emerged a maverick, now the number one pest of rice plants infesting two-thirds of our total lowland ricefield area of no less than two million hectares. Agriculturists have lately turned their attention to phytochemicals to control golden kuhol.  These are the plants they have confirmed to be effective. 

Neem tree and closeup of fruits. Azadirachta indica, also known as Neem, Nimtree, and Indian Lilac is a tree in the mahogany family Meliaceae. Wikipedia

·        

          Derris philippinensis (derris or tubli)

·         Manihot esculenta (cassava)

·         Chrysanthemum morifolium (chrysanthemum)

·         Capsicum anuum (pepper or siling labuyo)

·         Makabuhay

·         Neem 

Except for siling labuyo, the leaves and stems of any of these plants are either crushed or chopped finely and applied directly on the ricefield, controlling the water level up to three to four inches so as to allow the active ingredients to spread out and reach the pest in all of its stages. Where there are two or more of these plants growing in the area, farmers may use them in any combination, either alternately or simultaneously.~