How to Manage Pests
UC Pest Management Guidelines
(Reviewed 12/13, updated 12/13)
In this Guideline:
Optimal physical and chemical soil conditions result in healthy plants. Poor soils require remedial action in order to support healthy plants; this may take many years and can be expensive. Use the table below to compare tomato field requirements with the conditions of your prospective site. If there are specific site problems, you will need to determine if remediation is feasible. Proper field preparation is also essential for minimizing fertilizer and pesticide runoff.
|Hardpan, compacted soils
||Tomato grows successfully on a range of soil textures, but deep, loamy, well-drained soil with organic matter is preferred.
||Irrigate more often
|Clay soils with poor aeration
||Install drainage tiles
|Uneven topography, waterlogging
- Precise field leveling appropriate for irrigation system and providing for drainage at tail end
- Use of subsurface drip irrigation
- Install drainage tiles
|Nutrient deficiencies (nitrogen, phosphorus, and sometimes potassium)
||Fertilize if soil tests show deficiencies.
|Low pH (less than 6.0)
||Lime the soil
|High pH (greater than 7.5)
||Reclaim (see sodic soil below)
|Saline soil (ECe greater than 2.5 dS/m)
||Reclaim: leach excess salts below the root zone.
||Sites with excessive salts require major modifications that can be expensive.
|Sodic soil (SAR greater than 13)
||Remediation requires adequate soil calcium to replace sodium on soil cation exchange sites. If soil is low in calcium, apply gypsum (CaSO4). If soil has free lime (CaCO3) apply sulfur, which over time lowers soil pH and increases calcium solubility. In addition to ample soil calcium, sufficient leaching volume (from irrigation or rain) is required to move sodium below the root zone.
||Sites with excessive sodium require major modifications that can be expensive, and time consuming. Sodic soils are unsuitable for tomato production until effectively remediated.
|Seed or seedling pests (e.g., symphylans)
||Plow and disc old crop, cover crop, or other plant material that can harbor pests.
||Symphylans will likely persist and require chemical control
|Pathogens and nematodes
||Soil solarization, deep plowing to destroy sclerotia, fumigation, crop rotation to non-host
||Resistant varieties may be available. See VARIETY SELECTION.
- Apply preplant herbicide in fall or just before planting.
- Before planting in San Joaquin Valley, preirrigate the field and cultivate germinating weeds.
- Deep plow (9 to 10 inches) with a moldboard plow to reduce nightshade and nutsedge populations by burying seeds and tubers.
UC IPM Pest Management Guidelines:
UC ANR Publication
- R. M. Davis, Plant Pathology, UC Davis
- T. K. Hartz, Plant Sciences, UC Davis
- W. T. Lanini, Weed Science/Plant Sciences, UC Davis
- E. M. Miyao, UC Cooperative Extension, Yolo County
- C. J. Rivara, Calif. Tomato Res. Institute
- F. G. Zalom, Entomology, UC Davis
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