Updated: July 1, 2023

Mandarin plants, also known as mandarin oranges or tangerines, are popular fruit-bearing trees that can be found in many home gardens. However, one common problem that citrus growers often face is nematode infestation. Nematodes are microscopic roundworms that can cause significant damage to the roots of mandarin plants, leading to stunted growth, yellowing leaves, and decreased fruit production. Luckily, there are several strategies you can employ to effectively control and eliminate nematodes from your mandarin plant. In this article, we will explore these methods and provide you with step-by-step instructions to get rid of nematodes on your mandarin plant.

Step 1: Identify the Nematode Problem

Before you can begin treating the nematode infestation on your mandarin plant, it is important to confirm that nematodes are indeed the cause of the issues you are experiencing. Look for symptoms such as stunted growth, wilting leaves, yellowing foliage, and poor fruit production. Carefully dig around the root area of the plant and examine the roots for tiny knots or galls, which are characteristic signs of nematode damage.

Step 2: Remove and Destroy Affected Plants

If you have confirmed a nematode infestation on your mandarin plant, it is crucial to remove and destroy the affected plants as soon as possible to prevent further spread of the nematodes. Carefully uproot the plant, making sure to remove all of its roots from the soil. Place the infected plant in a plastic bag and dispose of it properly. Do not compost the infected plant material, as this can potentially spread the nematodes to other areas of your garden.

Step 3: Solarize the Soil

Solarization is an effective organic method to control nematodes in the soil. This process involves using the heat from the sun to kill nematodes and other soil-borne pathogens. To solarize the soil, follow these steps:

  1. Prepare the area: Clear the affected area of any debris, rocks, or weeds. Smooth out the soil surface as much as possible.

  2. Irrigate the soil: Moisture is essential for effective solarization. Water the area thoroughly to a depth of at least 12 inches.

  3. Cover the soil: Use a clear plastic tarp or sheet to cover the moistened soil completely. The plastic should be tightly secured around the edges to trap the heat inside.

  4. Leave it in place: Allow the plastic to remain on the soil for 4-6 weeks during the hottest period of the year. The heat trapped under the plastic will kill nematodes and other pests in the top few inches of soil.

Step 4: Rotate Crops

Crop rotation is an excellent long-term strategy to manage nematode populations in your garden. Avoid planting mandarin or any other citrus plants in the same area for at least three years after an infestation. Nematodes have specific host plants, and by rotating crops, you can disrupt their life cycle and reduce their numbers over time.

Instead of citrus, consider planting nematode-resistant crops such as marigolds, sunflowers, or mustard greens in the affected area. These plants produce compounds that repel nematodes and can help in reducing their population in the soil.

Step 5: Use Nematode-Resistant Rootstocks

When replanting mandarin trees, choose rootstock varieties that are resistant or tolerant to nematodes. Some common nematode-resistant rootstocks for citrus include Carrizo citrange, Troyer citrange, and Swingle citrumelo. These rootstocks have been bred specifically to resist nematode damage and can help prevent future infestations.

Step 6: Apply Beneficial Nematodes

Beneficial nematodes, such as Steinernema feltiae or Heterorhabditis bacteriophora, are natural predators of plant-parasitic nematodes. These microscopic organisms can be purchased from gardening stores and applied to the soil around your mandarin plant. Follow the package instructions for application rates and methods.

Beneficial nematodes actively seek out and infect plant-parasitic nematodes, ultimately killing them and reducing their population in the soil. It is important to note that beneficial nematodes are sensitive to environmental conditions, so make sure to apply them during the recommended temperature range for optimum effectiveness.

Conclusion

Nematode infestation can be a frustrating problem for mandarin plant growers. However, by following the steps outlined in this article, you can effectively control and eliminate nematodes from your garden. Remember to identify the nematode problem, remove and destroy affected plants, solarize the soil, rotate crops, use nematode-resistant rootstocks, and apply beneficial nematodes. By implementing these strategies, you can ensure the health and productivity of your mandarin plants for years to come.