To reduce management costs, select fields with desirable characteristics and a minimum of potential pest problems.
- Deep, well-drained, sandy loam soils are preferred for strawberry production because field preparation is easier, fumigation is more effective, accumulation of salts is less, drainage is better, and the soil is better suited to the frequent irrigation and field activity that strawberries require. Avoid poorly drained soils to minimize problems with root diseases such as Phytophthora root and crown rot.
- Choose fields that are easy to grade to the proper slope and have good air drainage so cold air doesn't settle in the field.
- Ensure an adequate supply of good-quality water. Make sure that soil and field conditions allow you to maximize use of available water to grow strawberries.
An accurate field history will help you evaluate the effectiveness of management actions and make long-term planning easier. (It may be useful to organize information in a spreadsheet, combining all data from a given field for several years in a single document.) For each field, keep records of:
- Routine field surveys, including dates and GPS locations;
- Weed surveys;
- Results of laboratory analyses such as soil tests, water tests, and pest identifications;
- Horticultural information, including cultivars, planting dates, source of transplants, harvest dates, and yields;
- Dates of pesticide applications, including pesticide names and rates, and their effectiveness.
Check Potential Problems Before Planting
Before you begin preparing your fields for planting, a number of monitoring activities are important in helping you plan your pest management program for the season.
- Consult field records for cropping history, cultural practices, pesticide use, and problems with pests, soil conditions, and salinity. Check plantback restrictions to be sure herbicides with long residual life were not used on the previous crop.
- Survey the field for weeds and record your results (example form— ). Avoid planting strawberries if infestations of field bindweed or yellow nutsedge or high densities of little mallow or burclover are present.
- Collect samples of irrigation water and field soil for analysis of salinity, nutrient levels, and microbial contaminants.
- Have the soil and water tested for salts and salinity. If the water supply has more than 900 to 1000 ppm total salts, special precautions will be needed to avoid injurious salt buildup. If salt levels are too high, you may want to avoid planting strawberries or else plan extra irrigations to rinse excess salts away from the strawberry root zone. Irrigations to reduce soil salinity are best done before preparing fields for fumigation and planting and can take years to improve conditions measurably.
- Have the soil tested for boron and zinc to assure optimum levels.
- Survey adjacent areas for pests that may move into strawberries: for example, infestations of twospotted spider mites, whiteflies, cutworms, or armyworms; weed hosts of lygus bugs; potential sources of root weevils; weeds with wind-dispersed seed; signs of vertebrate pests such as ground squirrels, gophers, voles, or moles.
- If possible, visit nurseries where you plan to get your transplants to learn about their pest control programs and management practices.
Rotating strawberries with a cover crop such as rye, barley, or a mix of barley and bell beans may enhance pest control and help improve soil structure. A heavy stand of cereal rye or barley provides additional weed control because these crops are very competitive with weeds and allow broadleaf herbicides to be used to control weeds that can be serious problems in strawberries. In addition, rye does not host some of the pests that attack strawberries and can help reduce root-knot nematodes and soil levels of Verticillium, although significant disease control requires long-term rotations.
Mustards generally are the best weed competitors among commonly used cover crops, and their residue breaks down faster compared to cereals. Additionally, mulched mustard residue might reduce viability of Phytophthora in the soil.
Rotation with vegetable crops may allow additional weed control options and provide economic returns. Incorporation of broccoli residues may reduce population levels of soil pathogens including Verticillium. Winter vegetable operations can result in soil compaction and deterioration of soil structure. Incorporation of cover crop residue loosens the soil and can help improve soil drainage. Be sure to allow enough time for the cover crop to decompose before preparing the field for strawberry planting.
Long-term use of soil amendments can improve soil structure and drainage.