Publication 360, Guide to Fruit Production: Nematode Control

Pub 360, Guide to Fruit Production > Chapter 9, Other Pests and Disorders > Nematode Control

Excerpt from Publication 360, Guide to Fruit Production, 2012-13
Order this publication

1. Nematode management
2. Cover crops for nematode suppression
3. Other cultural practices to reduce nematodes
4. Soil fumigation
   • Table 9-2. Control of Nematodes and and Other Soil-borne Pests before Planting Fruit Crops
5. Application of fumigants before planting
6. Fumigating single tree sites before planting replacement trees
7. Nematode suppression after planting
8. Other topics in Other Pests and Disorders
   • Nematodes - Symptoms and Thresholds
   • Deer Control
   • Mouse and Vole Control in Orchards
   • Controlling Rabbits
   • Bird Control
   • Control of Southwest Injury on Fruit Trees
   • Preventing Heat Stress and Fruit Sunburn on Apple and Pear Trees
9. Chapter 9 - Other Pests and Disorders - (PDF 113 kb)
10. Related Links

Nematode management

Use a combination of the following methods to manage nematodes:

• plant nematode-free transplants and seedlings
• rotate susceptible crops with non-host crops for several years
• plant nematode-suppressing cover crops
• destroy residual crop roots
• plant resistant fruit cultivars where available
• control weeds
• use soil fumigation when necessary

Cover crops for nematode suppression:

Examples of nematode-suppressing cover crops:

• oilseed radish
• certain oriental mustards cultivars like Forage or Cutlass
• specific sorghum × sudan-grass hybrids
• African marigold cultivars like Crackerjack or Creole
• Canadian Forage Pearl Millet 101

These cover crops can reduce plant parasitic nematode populations. Not all cultivars reduce nematode populations, so choose the right variety. One or more years of nematode-suppressing cover crops may be required to reduce nematodes below economic thresholds

Cover crops suppress nematodes in different ways.

• Canadian Forage Pearl Millet 101 is a poor host and inhibits the ability of root lesion nematodes to reproduce in its root-system.
• Certain cultivars of African marigolds produce a root exudate that kills nematodes in the soil.
• Nematode-suppressing cultivars of oilseed radish and certain oriental mustards produce isothiocyanate in their leaves, stems and petioles. This chemical is toxic to nematodes when the cover crop is cut green and incorporated immediately into the soil.

Exclude cover crops such as clovers and buckwheat from berry and orchard rotations. These are excellent hosts for root-lesion nematodes. Wheat or barley are the best cereal crops to grow before planting. For more information, see Table 3-18. Characteristics of Cover Crops.

Other cultural practices to reduce nematodes

Nematode populations can build on many weed species. A good weed control program is essential the year before planting fruit crops. Be sure to control weeds where nematode-suppressing cover crops are grown.

Keep land fallow the year before planting to reduce nematode numbers. A disadvantage to fallow land is increased susceptibility to soil erosion.

In orchards, choose ground covers between the rows that do not support nematodes, such as annual or perennial ryegrass.

Soil Fumigation

Pre-plant soil fumigation is the most effective method of controlling nematode problems. Fumigants can be broadcast over the whole field or applied only in bands where trees will be planted. Tree-row application, or the treatment of a 2-2.5 m strip centered on the row, is more economical. However, broadcast fumigation will reduce the risk of re-contamination if non-fumigated soil is mixed into the fumigated strip.

For products, rates and other information on fumigants refer to Table 9-2. Control of Nematodes and Other Soil-borne Pests before Planting Fruit Crops.

Application of fumigants before planting

Most fumigants are applied by shank injection using specialized application equipment. Some formulations of Vapam and Busan can be applied to the soil surface and watered in. See the product label for application instructions.

• Fumigate when soil temperatures are above 4°C. Warmer temperatures (15°C and over) are preferred for more rapid fumigant dispersal in the soil. Fumigation the fall before planting is best for fruit crops, which are planted in early spring when soils are still cool.
• Land preparation is critical for effective fumigant application. Remove trash and old root systems. One week prior to fumigation, work the soil to a depth of 25-30 cm and obtain good seedbed tilth and moisture. Keep soil moist and if necessary irrigate the treated area during the week prior to fumigation.
• Seal the soil surface by packing or watering immediately after injection of the fumigant. For best results, keep the soil surface moist during application and for 24 hours after application.
• Leave soil undisturbed for at least one week after injection of the fumigant. Colder soils (below 15°C) require longer periods from injection to aeration.
• Work the soil and aerate for about a week before planting. For fall planting, work the soil and aerate for two weeks before planting. The time interval between fumigation and planting into fumigated soil depends upon the product used, the rate and the temperature following fumigation (consult product label).
• Use high-quality planting stock, preferably grown in fumigated soil.
• Always read the product label.

• Soil drench and foliar spray: Treat young whips and non-bearing fruit trees with one application of Vydate L as a soil drench around the base of each tree when roots are actively growing and leaf growth begins in the spring. Follow this with a foliar application of Vydate L; or,
• Foliar application: Make three foliar applications on a two to three week schedule for a total of three applications. Do not allow spray to drift onto trees in bloom. Do not apply to trees under water stress or not actively growing.

• Treat raspberry plants with one application of Vydate L as a soil drench over roots in the fall before October 31. Do not apply Vydate L to raspberries in the spring. Do not apply to raspberries more than once a year.