Rolling out your Strategy

Once you have a thorough knowledge of the characteristics and needs of key pests and natural enemies, you're ready to begin designing a habitat-management strategy specifically for your farm.

■ Choose plants that offer multiple benefits — for example, ones that improve soil fertility, weed suppression and pest regulation — and that don't disrupt desirable farming practices.

■ Avoid potential conflicts. In California, planting blackberries around vineyards boosts populations of grape leafhopper parasites but can also exacerbate populations of the blue-green sharpshooter that spreads the vinekilling Pierce's disease.

■ In locating your selected plants and diversification designs over space and time, use the scale — field- or landscape-level — that is most consistent with your intended results.

And, finally, keep it simple. Your plan should be easy and inexpensive to implement and maintain, and you should be able to modify it as your needs change or your results warrant.

In this book, we have presented ideas and principles for designing and implementing healthy, pest-resilient farming systems. We have explained why reincorporating complexity and diversity is the first step toward sustainable pest management. Finally, we have described the pillars of agro-ecosystem health (Figure 1, p. 9):

■ Fostering crop habitats that support beneficial fauna

■ Developing soils rich in organic matter and microbial activity

Throughout, we have emphasized the advantages of polycultures over monocultures and, particularly, of reduced- or no-till perennial systems over intensive annual cropping schemes.

PREVENTIVE MANAGEMENT

pre-season through plantingtime (building internal strengths into the system)

build healthy soil (below ground habitat conservation and enhancement)

POST-PLANTING PLANNED MANAGEMENT

REACTIVE MANAGEMENT

(if yield or guality goals are not being achieved)

PREVENTIVE MANAGEMENT

pre-season through plantingtime (building internal strengths into the system)

build healthy soil (below ground habitat conservation and enhancement)

reactive pest management reactive pest management

OPTIMAL CROP YIELD AND QUALITY—WITH HIGH POSITIVE AND LOW NEGATIVE ENVIRONMENTAL EFFECTS

OVERALL GOAL

Figure 2. Preventive and reactive strategies that enhance ecological pest management. Adapted from Univ. of Vt., Dept. of Plant and Soil Sciences

Key Elements of Ecological Pest Management

Ecological Pest Management relies on preventive rather than reactive strategies. Your cropping program should focus primarily on preventive practices above and below ground (#1 and #2) to build your farm's natural defenses. Reactive management (#5 and #6) is reserved for problems not solved by the preventive or planned (#3 and #4) strategies.

OVERALL STRATEGIES:

— Build the strengths of natural systems into your agricultural landscape to enhance its inherent pest-fighting capacity.

— Enhance the efficiency of your farm, including cycling of nutrients, flow of energy, and/or the use of other resources.

These broad strategies and the individual practices that follow result in systems that are:

• Self-regulating — keeping populations of pests within acceptable boundaries

• Self-sufficient — with minimal need for "reactive" interventions

• Resistant to stresses such as drought, soil compaction, pest invasions

• Resilient - with the ability to bounce back from stresses

1) Crop management: above ground habitat conservation and enhancement of biodiversity within and surrounding crop fields. Use a variety of practices or strategies to maintain biodiversity, stress pests and/or enhance beneficial organisms.

• Select appropriate crops for your climate and soil

• Choose pest resistant, local varieties and well adapted cultivars

• Use legume-based crop rotations, alternating botanically unrelated crops

• Use cover crops intensively

• Manage field boundaries and in-field habitats (ecological islands) to attract beneficials, and trap or confuse insect pests

• Use proper sanitation management

• Consider intercropping and agroforestry systems

2) Soil management: below ground habitat conservation and enhancement.

Build healthy soil and maintain below ground biodiversity to stress pests, enhance beneficials and/or provide the best possible chemical, physical, and biological soil habitat for crops.

• Build and maintain soil organic matter with crop residues, manures and composts

• Reduce soil disturbance (tillage)

• Keep soil covered with crop residue or living plants

• Use cover crops routinely

• Use longer crop rotations to enhance soil microbial populations and break disease, insect and weed cycles

• Maintain nutrient levels that are sufficient for crops but do not cause imbalances in the plant, which can increase susceptibility to insects and diseases

• Maintain appropriate pH

• Control soil erosion and nutrient losses

• Avoid practices that cause soil compaction

3) Planned supplemental pest management practices. The following practices can be used if research and farmer experience indicate that - despite the use of comprehensive preventive management as outlined above - some additional specific pest management practices will still be needed:

• Release beneficial insects or apply least environmentally harmful biopesticides

• Prune to reduce humidity in the canopy and deter fungal infections

• Cultivate for weed control based on knowledge of critical competition period

4) Planned supplemental soil practices to reduce crop stress and/or optimize yield and quality

• Maintain adeguate soil water content (i.e., with careful irrigation scheduling)

• Mow rather than incorporate orchard cover crops, leaving a mulch cover

• Undersow legumes in cereals

5) Reactive inputs for pest management

If, after following preventive and planned management practices (#1, 2, 3, and 4), pests are above threshold levels and beneficials populations are low, release beneficials or apply selected biopesticides with low environmental impact.

6) Reactive inputs to reduce plant stress

• Use chisel plow or subsoiler to alleviate soil compaction

• Apply nutrients to soil or foliage in response to plant deficiency symptoms

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