eOrganic authors:
Helen Atthowe, Biodesign Farm
Alex Stone, Oregon State University
This article is part of the Biodesign Farm Organic System Description
Table 1. Insect Pest Management System
| Strategies and tools1 | Implementation details |
|---|---|
| I. Landscape-level design | |
| Design fields to favor biological control agents | Small crop fields were bordered on four sides by native grassland/pasture: pasture (75%), native grassland/dryland shrub-steppe community (15%), and riparian areas (10%) (Overview Fig. 2). |
| Practice temporal rotation | The 3-year rotation of crops was based on crop family (Solanaceae, Brassicaceae, Fabaceae). |
| Design for spatial diversity | Fields were bordered by native grassland and pasture habitat. Within fields, crops were diversified (some were allowed to mature and flower). Row middles consisted of clover/weed living mulches, which were allowed to flower. |
| II. Soil building for insect pest suppression | |
| Add organic soil amendments | Organic residues were applied regularly (mostly surface applied, with some incorporation of residues in the spring). Materials included mowed living mulch residue and on-farm-made compost. |
| Reduced tillage | Minimum tillage was practiced in the spring. In New field, tillage was done only in crop rows. |
| Optimize quantity and quality of soil organic matter (SOM) | Organic residues varied in carbon content and ease of decomposition. SOM increased from an average of 3.5 to 5.7% in Old field and from 3.3 to 5.2% in New field. |
| Increase below-ground plant diversity | A living mulch was planted between crop rows. The living mulch contained diverse annual and perennial species with different rooting types. |
| Optimize soil potassium levels | Potassium was supplied by the organic residues. Potassium levels increased and were relatively high. Old field: Potassium increased from 145 ppm in 1993 to 713 ppm in 2003, and decreased to 323 ppm after Biodesign stopped manure compost application. New field: Potassium increased from 123 ppm in 1993 to 229 ppm in 2010. |
| Match nitrogen supply with crop need | Applied organic residues gradually supplied nitrogen due to some with higher carbon: nitrogen ratios. |
| Optimize soil calcium levels and cation balance | Ca increased from an average of 1,588 to 2,024 ppm and decreased from 77.9 to 68.7% in the Old field.New field: Increased from an average of 1,485 to 1,790 ppm and decreased from 78.8 to 77.1%. |
| III. Habitat-building | See also Selective Mowing |
| Create diverse below-ground habitat | A living mulch was planted between crop rows. The living mulch contained diverse annual and perennial species with different rooting types. |
| Create diverse above-ground habitat at the landscape level | Diverse habitat (native grassland, riparian areas, and pasture) was maintained on 95% of field margins. Most roads on the farm were covered with grass or perennial living mulch. |
| Create diverse above-ground habitat at the field level | The living mulch contained diverse annual and perennial species. Between 30 and 50% of total acreage was planted in cover crops. Crops were diverse, and some were allowed to mature and flower in crop fields. The three main crops were solanaceous (60%), brassicas (30%), alliums (5%), and other crops (5%). |
| Use blooming winter and summer cover crops | The living mulch bloom sequence extended from early April through late September. Some species were allowed to flower during the entire cropping season due to selective and reduced mowing. |
| Provide winter cover and refuge for beneficial organisms | The living mulch provided year-round habitat and/or cover. |
| Install grassy beetle banks | Rather than installing beetle banks, Helen maintained undisturbed grassy areas on field borders and undisturbed clover/weeds in the living mulch between crop rows. A 30-ft x 600-ft remnant pasture strip was left in the middle of the 6-acre New field (2005–2010) as a beetle refuge. |
| Manage living mulch mowing to optimize predator/parasite populations | Selective and reduced mowing of the living mulch all season, especially in the spring, enhanced ground-dwelling predator populations and provided pest control. |
| IV. Monitoring and identification of insect pests/beneficials | |
| Scout crops and monitor for pests and beneficials | Scouting for insect and disease pests and beneficials was done every 5 to 20 days. |
| Identify pests and beneficials | Scouting for insect and disease pests and beneficials was done every 5 to 20 days. |
| Keep records | Spray records were kept, beginning in 1994. Pest incidence records were kept sporadically from 1994 to 2010. |
| Use monitoring data to inform management decisions | Sprays were applied only when pests reached a threshold, based on monitoring. On-farm thresholds were developed to include predator and parasite:pest ratios when natural enemy populations increased. |
| V. Supplemental inputs | |
| Use selective organic insecticides | Bt and M-pede (soap) were used to avoid killing beneficial insects (Table 2). |
| Reduce organic insecticide sprays | Insecticide use decreased and/or was eliminated from the 1990s through 2010 (Fig. 1). |
¹Strategy listed in the NRCS Soil Quality Initiative
Table 2. Pest-Specific Strategies, Biological Controls, Supplemental Pesticides and Outcomes
| Insect pest1 | Pest trend2 | System design/Management strategies | Biological controls3 | Off-farm inputs and supplemental pesticides |
|---|---|---|---|---|
| Aphids: many spp., especially green peach aphid (Myzus persicae)vand potato aphid (Macrosiphum cuphurbiae) Crops: pepper, eggplant, tomato, potato | DOWN | Landscape-level diversity, provided by small crop fields bordered on four sides by native grassland/pasture (Overview Fig. 2). | *Syrphids, spiders, lady beetles, lacewings, earwigs, parasitoid wasps (Aphidius and Aphelinus species), aphid midge (Aphidoletes aphidomyza) | 1995–2000: insecticidal soap (M-Pede) 2001–2010: no sprays |
| Cabbage aphids (Brevicoryne brassicae) Crops: brussels sprouts, broccoli | DOWN | Perennial and annual clover/weed living mulch in row middles to provide in-field/interspersed plant diversity, season-long pollen/nectar/seed food sources, and winter cover | *Syrphids, spiders, lady beetles, parasitoid wasps (Diaeretiella rapae) | |
| Cabbageworms: imported cabbageworm (Pieris rapae), diamondback moth (Plutella xylostella), and cabbage looper (Trichoplusia ni) Crops: broccoli, cabbage, brussels sprouts | DOWN | Reduced tillage | *Spiders, carabid beetles, lady beetles, lacewings, earwigs, nabid bugs, minute pirate bugs, birds | 1994–1998: Bt (Bacillus thuringiensis) 1998–2010: no sprays Hooped row covers |
| Brassica flea beetle (Phyllotreta cruciferae) Crops: broccoli | DOWN | Diverse crops (allowed to flower) and a 3-year rotation of crops by crop family (Solanaceae, Brassicaceae, Fabaceae) | **Carabid beetles, spiders | Hooped row covers placed over transplanted brassicas in the spring for frost protection and to suppress flea beetles |
| Solanaceous flea beetles: western potato flea beetle (Epitrix subcrinita) and potato flea beetle (Epitrix cucumeris) Crops: eggplant, tomato | DOWN | Selective mowing of the annual and perennial living mulch to avoid disturbance of natural enemies at key pest pressure times | **Carabid beetles, spiders | Management of overhead sprinkler irrigation to discourage flea beetles |
| Colorado potato beetle (Leptinotarsa decemlineata) Crops: eggplant, tomato | DOWN | Native shrub hedgerow (in New field only), planted 2005, matured 2006–2010 Perennial native plant insectary planting (New field only), planted 2005, matured 2006–2010 Perennial grass beetle bank (New field only), 2005–2010
| *Predaceous stink bugs (Perillus bioculatus and Podisus maculiventris) **lady beetles, carabid beetles, spiders | 1995 and 1997: Bt (Bacillus thuringiensis San Diego) 1998–2010: no sprays |
¹For a list of common pests and their management in Montana, see the High Plains Integrated Pest Management (HPIPM) Guide and the Pacific Northwest Insect Management Handbook.
²Supporting data is from spray records, farmer observations, crop monitoring records, and on-farm research.
³* = detected feeding on or parasitizing pests; ** = observed and hypothesized as control
This article is part of the Biodesign Farm Organic Systems Description.
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