Nature’s pest control methods

The fight against harmful fungi for plants using natural enemies.

One of the best way that is environmentally friendly is to control using antagonistic microbes. Antagonism means hostility, and in this case we are talking about natural enemies found in nature. This study, using cabbage as an example, shows an effective way to deal with a clubroot pathogen using an antagonistic microbe called Trichoderma. It should be noted that trichoderma also has a stimulating effect on plant growth.

Cabbage clubroot is a disease caused by the soilborne fungi. The pathogen is extremely common in various regions of the world, in particular, in Bali over the past ten years there has been a drop in cabbage yield by more than 25%, that is closely related to the attack of clubroot. Symptoms appear as yellowing, wilting, stunting, and galls on the roots.

In the experiment, each plant was treated with a different amount of Trichoderma: 1, 2 and 3 million spores per plant which were suspended in 150 ml of water. An organic nutrient lignohumate (LH) has also been added to further support plants that retain soil nutrients, improve soil structure and increase plant resistance to biotic and abiotic stresses. The lignohumate treatments were 0.01, 0.02, 0.05, 0.1, 0.5, 1.0, and 2%.

Both Trichoderma and LH individually led to a decrease in the cabbage clubroot (Table). LH through indirect exposure: by increasing their overall resistance to the pathogen; and trichoderma direct: due to the direct destruction of the pathogen. The best combination of LH with Trichoderma occurred at 0.5% LH and 15 g of Trichoderma which resulted to the lowest incidence of disease infection.

Disease incidence of clubroot on cabbage under treatment of lignohumate and Trichoderma (lower is better)

Role of Trichoderma  not only suppresses the growth of pathogens, but there are other influences that are beneficial for plants, namely increasing plant defenses, stimulating colonization by the rhizosphere microbes and stimulating plant root growth. 

The figure shows an example of the effect of trichoderma on plant roots: on the left, healthy roots treated with trichoderma and LH; on the right – the roots affected by the clubroot pathogen

In combination with LH, Trichoderma increases the mass of the aerial parts of plants and the amount of chlorophyll in the tissues, which favorably affects the quality of the resulting crop. Also, LH are able to increase soil biological activity, and this is considered to be one of the probable mechanisms of their positive effect on plant growth and development.

Full Text:

Suada, I. K., Suwastika, A. A. N. G., Pradnyana, I. K. N., Shchegolkova, N., Poloskin, R., Gladkov, O., … & Stepanov, A. APPLICATION OF Trichoderma spp. AND LIGNOHUMATE TO SUPPRESS A PATHOGEN OF CLUBROOT (Plasmodiophora brassicae WOR.) AND PROMOTE PLANT GROWTH OF CABBAGE. International Journal of Biosciences and Biotechnology, 6(2), 79-94.