Midwest Vegetable Guide - 2022 - 83

Asparagus - Diseases
Fertilizing
pH: Maintain a soil pH of 6.7 to 7.0. If possible, apply lime
the year before planting.
New plantings: Before planting new crowns, apply 50
pounds N per acre, 0 to 160 pounds P2O5 per acre, and 0 to
150 pounds K2O per acre based on soil test results and
recommendations from your state. Broadcast the fertilizer and
plow it under when preparing the land for the planting
furrows. In addition, apply 30 pounds P2O5 per acre in the
bottom of the trench and cover with 1 inch of soil before
setting crowns. For transplanted seedlings, apply 4 ounces of
transplant solution (e.g. 2-3 lbs. of 10-52-17 or 9-45-15 in 50
gallons of water) to each transplant.
Established plantings: Each year before emergence, apply
20 to 40 pounds N per acre by broadcasting and incorporate
by lightly tilling. After harvests conclude, apply 40 to 60
pounds N per acre. The total amount of N from fertilizer
should be 80 pounds N per acre. No P2O5 is necessary if
adequate fertilization was achieved prior to planting. Every
second year apply up to 60 pounds K2O per acre if a soil test
recommends it.
Harvesting
Harvest only 2 or 3 times in spring 1 year after transplanting.
Thereafter, harvest for about 2 months in the spring. Harvest
asparagus early in the morning for best quality. Allow the
ferns to grow vigorously after this period to accumulate food
reserves for the next season. As much care should be put into
maintaining a healthy fern as into harvest.
Asparagus - Diseases
Reviewed by Dan Egel, Mary Hausbeck - Sept 2021
Recommended Controls
Crown and Root Rot of Asparagus -
Fusarium Fungus
The Fusarium pathogen can be seed borne. Try to source
material for new plantings from fields fumigated with
chloropicrin.
Non-Pesticide
The disease is promoted by acidic (low pH) and poorly
drained soil. Establish production fields with blemish-free
crowns produced in virgin soil. Avoid fields with a history of
crown and root rot. Use tolerant, vigorous varieties if
available, and avoid long harvest periods to maintain vigor in
the plant over years.
Pesticide
Cannonball (50WP) (fludioxonil) | 0.5 oz. per 100 gals. of
water. Michigan only (MI 24c exp. 12/31/22). Submerge and
soak crowns for 10 minutes and allow to drain before
planting. REI: 12-hour. PHI: 365-day. FRAC 12.
Crown and Spear Rot of Asparagus -
Phytophthora Oomycete
Non-Pesticide
Avoid excessive irrigation. Choose well-drained planting
sites. Establish production fields from blemish-free crowns
obtained from virgin soil. Avoid long harvest periods to
maintain vigor in the plant over years.
Pesticide
metalaxyl 2E (metalaxyl) Celery | 2 pts. per acre. Use as
broadcast spray in a minimum of 10 gals. of water over the
beds. Cutting beds: Apply 30-60 days before the first cutting.
For additional control, make another application just before
the beginning of harvest. New Plantings: Apply after planting
seedlings or after covering one-year-old crowns. formulations
are labeled. REI: 48-hour. PHI: 1-day. FRAC 04.
Orondis Gold 200 SC (oxathiapiprolin) | 4.8-9.6 fl. oz. per
acre. Use 10 Gals of water, or the volume required to fully
submerge 100 crowns. Use as a crown soak prior to planting.
REI: 4-hour. PHI: 0-day. FRAC 49.
phosphite and phosphorous acid products (phosphorous
acid, potassium phosphite, mono-dipotassium salts of
phosphorous acid, mono- and dibasic sodium, potassium,
and ammonium phosphites, fosetyl-aluminum) | Rates
vary depending on formulation and product. Apply the
product to fully expanded ferns. Do not apply to ferns that are
beginning to senesce. Thorough coverage is required. REI: 4
to 12-hour. PHI: See label. FRAC 33.
Ridomil Gold SL (4SC) (mefenoxam) | 1 pt. per acre. Apply
30 to 60 days before the first cutting. Apply again just before
the beginning of harvest. Other formulations include
MetaStar, Subdue Maxx, Ultra Flourish, and Xyler. Rates
vary by formulation. REI: 48-hour. PHI: 1-day. FRAC 04.
Purple Spot of Asparagus - Stemphylium
Fungus
Weather forecasting tools, such as TOM-CAST, can help
asparagus farmers schedule their fungicide applications for
Midwest Veg Guide 2022
83
Midwest Vegetable Guide - 2022

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