7 Disease Management
7.1 Fern Diseases: Rust, Puccinia asparagi, Purple Spot, Stemphylium vesicarium, and other fern diseases
Time for concern: Late spring through end of season.
Key characteristics: Rust: red or brown elongated spots appear on spears or ferns. Ferns may prematurely yellow and brown. Purple spot: occurs on both ferns and spears. On spears lesions are slightly sunken and dark purplish. On ferns the lesions are slightly darker with a purplish-red margin. When disease is severe, needles will drop, leading to defoliation of the fern. When these diseases affect marketability of spears, fungicides need to be applied to ferns for control. See Michigan State Extension Bulletin E3219, Disease and Insect Pests of Asparagus.
| Management Option | Recommendations for Fern Diseases |
|---|---|
| Resistant varieties | Plant varieties resistant to rust whenever possible. See Table 1.1: Recommended Asparagus Varieties. |
| Site selection | Grow asparagus in fields that have never grown the crop before. Choose fields with good drainage. Plant in areas of good air circulation as heavy dew favors disease development. Stemphylium vesicarium also infects onions. Avoid establishing an asparagus planting less than three years after onions. Avoid planting onions close to asparagus plantings. |
| Scouting/thresholds | Record the occurrence and severity of rust. No thresholds are available. |
| Postharvest | Apply fungicides as a postharvest spray in mid-August or as disease appears. Control is important to reduce stress, which increases the incidence of Fusarium root rot. |
| Sanitation | In late fall or winter, remove and destroy fern residue. If permitted, burn residue to control both diseases. |
At the time this guide was produced, the following materials were registered in New York State, labeled for managing this pest, and allowed for organic production. The status of pesticides can and does change. To be used legally in NY, pesticides must be currently registered with the New York State Department of Environmental Conservation (DEC). However, pesticides meeting the federal requirements for minimum-risk (25(b)) pesticides do not currently require registration. Current NY pesticide registrations can be confirmed on the NY DEC Bureau of Pesticides Management Information Portal. ALWAYS CHECK WITH YOUR CERTIFIER before using a new product. |
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7.1 Fern Diseases: Rust, Puccinia asparagi, Purple Spot, Stemphylium vesicarium, and other fern diseases
7.2 Fusarium Root Rot and Fusarium Crown Rot, Fusarium spp.
Time for concern: Planting through life of bed.
Key characteristics: Fusarium causes weak, spindly spear production and overall reduced vigor over time. Feeder roots become rotted and discolored. Affected crowns show reddish brown discoloration when cut. If asparagus beds are experiencing dieback from Fusarium, you may want to investigate whether asparagus miner (Section 8.2) is part of the problem. See Michigan State Extension Bulletin E3219, Disease and Insect Pests of Asparagus.
| Management Option | Recommendations for Fusarium Root Rot & Fusarium Crown Rot |
|---|---|
| Resistant varieties | No varieties are resistant, but the recommended varieties in Section 1, Table 1.1 are more tolerant than older standards. Vigorous plants are less likely to be affected. |
| Site selection | Choose a field with good drainage. Grow asparagus in fields that have never grown the crop before. |
| Crown selection/ treatment | Buy disease-free crowns. New Jersey provides a list of Registered wholesale seedsmen that certify high-quality seed with a minimum of seedborne diseases. Consult with your supplier to determine how they maintain quality planting material. |
| Scouting/thresholds | No thresholds are available. |
| Postharvest and Sanitation | These are not currently viable management options. |
At the time this guide was produced, the following materials were registered in New York State, labeled for managing this pest, and allowed for organic production. The status of pesticides can and does change. To be used legally in NY, pesticides must be currently registered with the New York State Department of Environmental Conservation (DEC). However, pesticides meeting the federal requirements for minimum-risk (25(b)) pesticides do not currently require registration. Current NY pesticide registrations can be confirmed on the NY DEC Bureau of Pesticides Management Information Portal. ALWAYS CHECK WITH YOUR CERTIFIER before using a new product. |
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7.3 Phytophthora Spear and Crown Rot, Phytophthora spp.
Time for concern: This disease is currently not a problem in New York State, but its potential for occurring on Long Island is high.
Key characteristics: Infected spears show gray-beige to brown lesions slightly above or just below the soil line. The decay is odorless unless invaded by saprophytic bacteria. See description in Michigan State University Bulletin E3219: Disease and insect pests of asparagus.
| Management Option | Recommendations for Phytophthora Spear and Crown Rot |
|---|---|
| Resistant varieties | No resistant varieties are available. |
| Site selection | This is a problem in low or poorly drained areas. |
| Scouting/thresholds | Record the occurrence and severity of Phytophthora spear rot. No thresholds have been established. |
| Postharvest and Sanitation | These are not currently viable management options. |
At the time this guide was produced, the following materials were registered in New York State, labeled for managing this pest, and allowed for organic production. The status of pesticides can and does change. To be used legally in NY, pesticides must be currently registered with the New York State Department of Environmental Conservation (DEC). However, pesticides meeting the federal requirements for minimum-risk (25(b)) pesticides do not currently require registration. Current NY pesticide registrations can be confirmed on the NY DEC Bureau of Pesticides Management Information Portal ALWAYS CHECK WITH YOUR CERTIFIER before using a new product. |
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