Posted on

How to Manage Anthracnose in Watermelon

Anthracnose in Watermelon

Over the years, the demand for watermelon has been increasing rapidly, both locally and internationally. Watermelon has become a crucial part of most fruit salads. It is common to find melon slices served in groceries, alongside lunches during weddings, conferences, cooperate retreats, and also at homes. The success of watermelon farming, however, depends on the quality of fruits and the overall yield. When the fruits are affected by pests and diseases, most likely, nobody will be willing to buy them. Anthracnose is a destructive fungal disease that can ruin your watermelon farming venture if it is not controlled. If not controlled, it can damage the fruits and lead to vine death. When the plants are severely infected, especially when there are numerous lesions, anthracnose causes vine defoliation leading to low-quality fruits and a significant yield reduction.

Symptoms of Anthracnose in Watermelon

This disease is common in cucurbits such as melon and cucumber. At its early stages, water-soaked spots appear on the leaves which become brown as the disease progresses. Eventually, these spots darken and expand over the surfaces with the foliar lesions developing cracked centers. When stems and petioles are infected, they develop shallow, elongated, tan lesions that girdle the stem resulting to plant wilting. Infected fruits form circular, sunken, black lesions, providing an ideal environment for the formation of acervuli (small fruiting bodies). Under humid conditions, acervuli produce conidia which makes the lesions to have a pinkish color, a unique characteristic of anthracnose. When the disease gets to the pedicels of young fruits, the fruit either abort or shrivel.

Conditions for Disease development

Colletotrichum orbiculare, the causative agent of anthracnose, mostly comes in the seed or infected crop debris. The fungus can be spread by overhead irrigation, insects, splashing water, farm equipment, and field workers. The development of the disease is favored by warm weather and high humidity. The optimum temperature for anthracnose is 24°C. Later infection may inhibit the marketability of the fruits during storage, shipping, and display.

How to Control Anthracnose in Watermelon

The disease develops and spreads in warm, moist conditions, although the fungus can be carried in seeds, and infected debris. Infected vines should, therefore, be removed from the farm and destroyed. Farmers can also implement a comprehensive preventative fungicide program to prevent anthracnose.

Non-chemical control method

  • Avoid composting infected plants. Instead, they should be removed and destroyed.
  • Use varieties resistant from anthracnose.
  • Plant certified watermelon seeds and healthy plants.
  • Plant trees in well-drained soil.
  • Plant the watermelon in well-drained soils.
  • Ensure constant crop rotation with non-host plants such as cucurbits and French beans every 2 to 3 years.
  • To prevent wetting the foliage, avoid overhead irrigation. Also, avoid touching the plants when they are wet.
  • Control all weeds especially the volunteer cucurbits since they can host the anthracnose fungus.
  • Control all weeds, especially wild and volunteer cucurbits
  • Avoid wounding to prevent post-harvest losses since anthracnose can develop and the wounded part of the harvested fruit.

If the disease is controlled, watermelon farming is a disease that can rake you millions of money. The demand for watermelon is yet to be met and hence this is the venture one can consider.