Many of our local plants contain helpful chemicals, particularly alkaloids, that are effective against fungal and bacterial diseases of other plants. Thus, they are mixed with the soil to control the fungus that causes the diseases of seedlings. Allow the leaves to decompose for about one week before transplanting the seedlings.

bio-control on avocado

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Some of these leaves are as follows:
* abaca leaves
* avocado
* alibangbang
* acacia
* ampalaya
* atis
* guavas
* coconut
* calamansi
* star-apple
* chico
* garlic orchid
* datiles
* rimas
* onions
* papaya
* cacao
* cassava
* calachuchi
* sampaloc
* kakawate
* lanzones
* ginger
* malunggay
* cowpea
* sampaguita
* santan pula
* santol
* jackfruit
* tanglad
* eggplant
* beans (red variety)
* chichirica
* upo
* sugarcane
* watermelon
* tobacco
* saluyot

Thus, using plant leaves in controlling disease-causing organisms is no doubt cheaper than pesticides and insecticides. It is also simpler and easier to apply by merely incorporating the leaves with soil during cultivation. When decomposed, the leaves release certain chemicals which prevents harmful bacteria and fungi from attacking the crops. Besides controlling diseases, the leaves also increase the organic matter content of the soil,
improving its structure and fertility.

Source: Philippine Farmers’ Journal June 1982