Radish

Radish Disease Control Radish Insect Control Radish Weed Control

Introduction

Radish (Raphanus sativus), a member of the Brassicaceae family, is a very old crop, possibly important as early as 5,000 years ago. Present-day radishes include European radishes with relatively small roots as well as the large-rooted white daikons that are used both as food and as a cover crop, due to long taproots that can penetrate compacted soil.

Radishes grow very quickly, maturing in 21–28 days under ideal conditions. In cold weather, 40–50 days may be required. Preferred planting dates are early spring and August. The roots (technically swollen hypocotyls and roots) are spicy, due to the presence of glucosinolates, which are sulfur-containing compounds produced by members of the brassica family. High temperatures and a lack of moisture can increase both pungency and the speed of bolting. As a result, production in the spring and fall often results in higher quality radishes than those produced in the summer. Some varieties also have a tendency to become pithy, possibly in response to certain environmental conditions.

Types and Varieties

Table radishes come in an array of shapes (round, cylindrical, turnip-like) and colors (white, green, red, and black). Daikon is a general term for a group of long, white radishes that need cool temperatures and short day lengths to flourish. Some of these can grow up to 18" long and weigh about 3 lb on average, but can reach almost 50 lb.

Type	Varieties
Small, Round	Champion Cherriette Cherry Belle Crunchy King Crunchy Royale Early Scarlet Globe Easter Egg (red, white, and purple) Fireball Pearl (white) Purple Plum (purple) Red Satin Rover
Slender	D'Avignon (red and white) French Breakfast (red and white) Nelson (red and white) Shunkyo (red) White Icicle (white)
Storage Types	April Cross (Japanese daikon) Black Spanish (black) Cheong Du (Korean daikon) Green Meat Luobo (green) KN-Bravo (purple Korean daikon) Miyashige (Japanese daikon) Nero Tondo (black) Purple Heart (watermelon) Red King (red) Red Meat (watermelon) Starburst (watermelon) Summer Cross No. 3 (Japanese daikon) Summit (Korean daikon)

Type

Varieties

Small, Round

Champion

Cherriette

Cherry Belle

Crunchy King

Crunchy Royale

Early Scarlet Globe

Easter Egg (red, white, and purple)

Fireball

Pearl (white)

Purple Plum (purple)

Red Satin

Rover

Slender

D'Avignon (red and white)

French Breakfast (red and white)

Nelson (red and white)

Shunkyo (red)

White Icicle (white)

Storage Types

April Cross (Japanese daikon)

Black Spanish (black)

Cheong Du (Korean daikon)

Green Meat Luobo (green)

KN-Bravo (purple Korean daikon)

Miyashige (Japanese daikon)

Nero Tondo (black)

Purple Heart (watermelon)

Red King (red)

Red Meat (watermelon)

Starburst (watermelon)

Summer Cross No. 3 (Japanese daikon)

Summit (Korean daikon)

Soil Fertility

Apply lime according to soil test results to maintain soil pH at 6.0–6.8. Radishes need loose, well-drained soil for easy root expansion. Although daikon can penetrate heavy soils to depths more than 1', the roots will not be smooth, uniform and tender in heavy soils. In stony or very heavy soil, shorter daikon varieties perform better. Because radishes grow so rapidly, a rich, fertile soil is essential. They prefer cool growing conditions (50ºF–65ºF), so maintain a high level of soil moisture to minimize the adverse effects of summer temperatures.

Less nitrogen fertilizer will be needed if legume sod was plowed down or if manure was applied (see Table 1 and Table 7).

Plant Nutrient Recommendations According to Soil Test Results for Radish

SOIL TEST RESULTS	NITROGEN (N) - LB PER ACRE	PHOSPHORUS (P) - LB P₂O₅ PER ACRE				POTASSIUM (K) - LB K₂O PER ACRE
SOIL TEST RESULTS	NITROGEN (N) - LB PER ACRE	VERY LOW	LOW	OPTIMUM	ABOVE OPTIMUM	VERY LOW	LOW	OPTIMUM	ABOVE OPTIMUM
Broadcast and Incorporate	50	150	100	25–50	0	125	100	50	0–25
TOTAL RECOMMENDED	50	150	100	25–50	0	125	100	50	0–25

Planting

Radishes should be direct seeded, not transplanted. The seeding rate for table radish is 18–38 lb of seed/A (depending on variety) or 1.4 oz/100 rowfeet. The seeding rate for storage radishes is 7 lb/A.

Spacing. Seed radish 0.25"–0.5" deep, spaced at 0.75"–1" apart within the row (to obtain 12–15 plants per foot of row). Space rows 8"–15" apart. It is not recommended to transplant radish.

In the spring, plant as soon as the soil can be worked; thereafter, plant at intervals of about 10 days. Soft, well-tilled ground will result in the most attractively-shaped radishes. Radishes are often planted in 4-ft-wide raised beds, in 3–6 rows per bed. Use of floating row covers at time of planting will help control flea beetles and cabbage root maggots. Keep soil moist, especially if growing in hot conditions. Hot weather reduces quality and increases pungency. Late plantings may bolt before edible roots form.

Harvest and Storage

Yield. Some table radishes and most storage radishes are marketed with tops removed in plastic bags. Bunched radishes are common at farmers' markets and smaller retail operations. Those sold with tops will lose moisture and quality more rapidly than those without leaves. A good yield of bunched table radish is 2,500 dozen bunches (8–12 radishes/bunch) per acre (about 25 bunches per 30 ft of row). A good yield of film-packed radishes (8 oz bags) is about 15–20 bags per 30 ft of row. Daikon may be marketed in cartons or 20 lb plastic bags and good yields range from 15 to 20 tons/A.

Table Radishes. Harvest approximately 3–4 weeks after seeding when roots are the size of a large marble (depending on variety). Over-mature salad radishes may become pithy or split. Bunch or top, hydrocool, and refrigerate. Topped radishes will keep 3–4 weeks in good, crisp condition if kept at 32º F, 95% RH, and in breathable packaging.

Storage Radishes. Harvest approximately 60 days after planting. Daikon can be sold with or without the tops attached; usually a better price is paid for tops left on the roots. Storage radishes will last 3–4 months at 32º and 95% RH.

Radish Disease Control

Radish - General Radish Insect Control Radish Weed Control

Alternaria Leaf Spot (Alternaria spp.)

Symptoms include round, brown to gray lesions, sometimes with black, concentric rings, dark borders, and yellow haloes. The centers of the lesions may drop out over time, producing a “shot-hole” appearance. Severe infection may lead to defoliation. Alternaria leaf spot fungi do not affect radish roots but can reduce root yields if severe and will reduce the value of fresh-packed plants that retain the foliage. Buy certified disease-free seed or hot-water treat seed. Control brassica weeds and plow under crop debris in the fall. Rotate with non-brassica crops.

FRAC Group 7:

penthiopyrad (Fontelis): 14 to 30 fl oz/A; PHI 0d, REI 12h.

FRAC Group 9:

cyprodinil + fludioxonil (Switch 6.25 WG): 11 to 14 oz/A; PHI 7d, REI 12h, Groups 9 & 12.

FRAC Group 11:

azoxystrobin (Abound F aka Quadris F): 6 to 20 fl oz/A; PHI 0d, REI 4h. Do not rotate with other Group 11 fungicides.
pyraclostrobin (Cabrio EG): 8 to 12 oz/A; PHI 0d, REI 12h. Do not alternate with other Group 11 fungicides.

FRAC Group 12:

cyprodinil + fludioxonil (Switch 6.25 WG): 11 to 14 oz/A; PHI 7d, REI 12h, Groups 9 & 12.

FRAC Group BM02:

Bacillus amyloliquefaciens strain D747 (Double Nickel 55^OG): 0.25 to 3 lb/A (foliar); PHI 0d, REI 4h.
Bacillus subtilis Strain QST 713 (Serenade Max^OG): 1 to 3 lb/A; PHI 0d, REI 4h. Begin applications soon after emergence and when conditions favor disease. Apply in sufficient water to provide thorough coverage.

Downy Mildew (Hyaloperonospora brassicae)

This disease occurs worldwide, affects most brassicas, and is most important at the seedling stage. Cool, humid weather is conducive to disease development. Foliar symptoms include yellow, angular spots on upper leaf surfaces and grayish-white, fuzzy sporulation on the undersides. Leaves eventually turn brown. The pathogen can infect the fleshy root, causing external black patches, lesions on the root shoulder, and internal grey or black flecking and streaking. The root surface is scarred, prone to cracking or splitting, and unmarketable. Plant in well-drained soil and implement good cultural practices to facilitate air circulation. Plant resistant or tolerant cultivars.

FRAC Group M01:

copper oxychloride + copper hydroxide (Badge X2^OG): 1 to 2.25 lb/A; PHI 0d, REI 48h. Begin application when disease first appears or when conditions favor disease.

Seed Decay

Purchase treated seed. Do not use treated seed for food, feed, or oil purposes.

FRAC Group 4:

mefenoxam (Apron XL SL): 0.085 to 0.64 fl oz/100 lb seed; REI 48h.
mefenoxam (Ridomil Gold SL): 1 to 2 pt/A; REI 48h. Pre-plant incorporated or soil spray broadcast or band.

FRAC Group 11:

azoxystrobin (Abound F aka Quadris F): 0.4 to 0.8 fl oz/1000 row feet; PHI 0d, REI 4h.

FRAC Group 12:

fludioxonil (Maxim 4FS): 0.08 to 0.16 oz/100 lb seed; REI 12h. For protection against seedborne and soilborne fungi. Does not control Pythium or Phytophthora.

FRAC Group 43:

fluopicolide (V-10161 4SC, aka Presidio): 3 to 4.0 fl oz/A; PHI 7d, REI 12h. For Pythium control. Apply as banded spray. Application at seeding may help control downy mildew.

FRAC Group BM02:

Bacillus amyloliquefaciens strain D747 (Double Nickel 55^OG): 0.25 to 3 lb/A (foliar); PHI 0d, REI 4h.

White Rust (Albugo candida and A. cruciferarum)

Yield reductions caused by white rust are rare, but quality is reduced by the prominent, raised white spore masses on the undersides of leaves. On radish, white rust can also infect flower shoots and cause root swellings. Use resistant cultivars where available and rotate to non-brassica crops where the disease is common. Proper fertility levels, especially of phosphorus and potassium, have been reported to reduce disease.

FRAC Group 11:

azoxystrobin (Abound F aka Quadris F): 6 to 20 fl oz/A; PHI 0d, REI 4h. Do not make more than 1 foliar application before alternating with a non-Group 11 fungicide.
pyraclostrobin (Cabrio EG): 8 to 16 oz/A; PHI 0d, REI 12h. Do not rotate with other Group 11 fungicides.

FRAC Group M01:

copper oxychloride + copper hydroxide (Badge X2^OG): 1 to 2.25 lb/A; PHI 0d, REI 48h. Begin application when disease first appears or when conditions favor disease.

Disease Control

Radish Insect Control

Radish - General Radish Disease Control Radish Weed Control

Cabbage Maggot (Delia radicum)

Cabbage maggot can be excluded from brassica crops with spunbonded row covers. Cover at seeding and seal the edges with soil to exclude the adult fly, which lays eggs at the base of young radish seedlings. Do not plant into land that was occupied by a brassica crop the previous year, as this pest overwinters as pupae in soils that housed infested plants.

See the Cabbage, Broccoli, Cauliflower, and other Brassica Crops insect control section for more information about cabbage maggot.

IRAC Group 28:

cyantraniliprole (Verimark): 10 to 13.5 oz/A; PHI 0d, REI 4h, Bee: H. For soil applications at planting. Suppression only.

Cutworms

See the Pepper and Tomato (Outdoor) insect control sections for information on black and variegated cutworms.

IRAC Group 1:

carbaryl (10% Sevin Granules): 20 lb/A; PHI 7d, REI 12h, Bee: H, Group 1A. Apply evenly over soil surface.

IRAC Group 3:

alpha-cypermethrin (Fastac* CS): 1.3 to 3.8 oz/A; PHI 1d, REI 12h, Bee: H.
beta-cyfluthrin (Baythroid* XL): 1.6 to 2.8 oz/A; PHI 0d, REI 12h, Bee: H.
bifenthrin (Brigade* 2EC): 5.12 to 6.4 oz/A; PHI 21d, REI 12h, Bee: H.
deltamethrin (Delta Gold*): 1 to 2.4 oz/A; PHI 3d, REI 12h, Bee: H.

IRAC Group 5:

spinosad (Seduce^OG): 20 to 44 lb/A, 0.5 to1 lb/1000 sq ft.; PHI 3d, REI 4h, Bee: M. Spread bait on soil around plants.

IRAC Group 11:

Bacillus thuringiensis aizawai (XenTari^OG): 0.5 to 1.5 lb/A; PHI 0d, REI 4h, Bee: L. Must be ingested. For resistance management, may be rotated with Bt kurstaki products (Dipel).
Bacillus thuringiensis kurstaki (Dipel DF^OG): 0.5 to 2 lb/A; PHI 0d, REI 4h, Bee: L. Must be ingested. For resistance management, may be rotated with Bt aizawai products (XenTari).

IRAC Group 18:

methoxyfenozide (Intrepid 2F): 8 to 16 oz/A; PHI 1d, REI 4h, Bee: L. Suppression only.

Flea Beetle, Crucifer (Phyllotreta cruciferae) and Striped (P. striolata)

See the Cabbage, Broccoli, Cauliflower, and Other Brassica Crops insect control section for information on flea beetles that attack brassica crops.

IRAC Group 1:

carbaryl (Sevin XLR Plus): 0.5 to 1 qt/A; PHI 7d, REI 12h, Bee: H, Group 1A. Do not apply to crops or weeds in bloom.

IRAC Group 3:

alpha-cypermethrin (Fastac* CS): 1.8 to 3.8 oz/A; PHI 1d, REI 12h, Bee: H.
beta-cyfluthrin (Baythroid* XL): 1.6 to 2.8 oz/A; PHI 0d, REI 12h, Bee: H.
bifenthrin (Brigade* 2EC): 5.12 to 6.4 oz/A; PHI 21d, REI 12h, Bee: H.
deltamethrin (Delta Gold*): 1.5 to 2.4 oz/A; PHI 3d, REI 12h, Bee: H.
esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 7d, REI 12h, Bee: H.
pyrethrin (PyGanic EC5.0^OG): 4.5 to 15.61 oz/A, or 0.25 to 0.50 oz/gal and 3 gal/1000 sq ft in greenhouse for backpack sprayers; PHI 0d, REI 12h, Bee: M.

IRAC Group 4:

imidacloprid (Admire Pro): 4.4 to 10.5 oz/A soil, 1.2 oz/A foliar; PHI 21d soil, 7d foliar, REI 12h, Bee: H, Group 4A.
thiamethoxam (Actara): 1.5 to 3 oz/A; PHI 7d, REI 12h, Bee: H, Group 4A.
thiamethoxam (Platinum 75SG): 1.7 to 2.17 oz/A; REI 12h, Bee: H, Group 4A. Systemic insecticide used at planting.

IRAC Group 5:

spinetoram (Radiant SC): 6 to 8 oz/A; PHI 7d, REI 4h, Bee: M. Suppression only.
spinosad (Entrust SC^OG): 3 to 6 oz/A; PHI 3d, REI 4h, Bee: M.

IRAC Group UN:

kaolin (Surround WP^OG): 25 to 50 lb/A, 0.25 to 0.5 lb/gal; PHI 0d, REI 4h, Bee: L. Suppression only. Supplemental controls may be needed for complete control.
mineral oil (SuffOil-X^OG): 1 to 2 gal/100 gal; PHI 0d, REI 4h, Bee: L. Apply as needed for beetle larvae control.

Insect Control

Radish Weed Control

Radish - General Radish Disease Control Radish Insect Control

See section Soil Fumigation Outdoors in the Disease Management section. Proper use of Vapam can provide weed control and will be more economical if multiple plantings are used.

Stale Seedbed

The following herbicides are nonselective and are used to control weeds that are present in a field prior to planting or before the crop emerges, which is especially useful for the Stale Seedbed Technique (see the Weed Management section for more information).

glyphosate (Roundup Power Max): PHI 14d, REI 4h, Group 9.
pelargonic acid (Scythe): PHI 1d, REI 12h, Group 0.

Preemergent Herbicides (before weeds germinate)

HRAC Group 3:

trifluralin (Treflan HFP): 1 to 1.5 pt/A; REI 12h. 1 application per year. Apply and incorporate before planting; a second incorporation pass in the opposite direction may be required.

Postemergent Herbicides (after weeds germinate)

HRAC Group 0:

pelargonic acid (Scythe): 3% to 10% solution; PHI 1d, REI 12h. Apply for vegetative burndown during site preparation, prior to crop emergence from soil, as a directed and shielded spray, or as a harvest aid. Contact with crop will cause damage.

HRAC Group 1:

clethodim (Select Max): 9 to 16 fl oz/A; PHI 15d, REI 24h. Do not exceed 32 fl oz/A per year. Apply to actively growing grasses.
sethoxydim (Poast): 0.5 to 2.5 pt/A; PHI 14d, REI 12h. 1 application per year. Apply to actively growing grasses. BASF has stopped production and will discontinue the registration at the end of 2027.

HRAC Group 9:

glyphosate (Roundup Power Max): 10 fl oz to 3.1 qt/A; PHI 14d, REI 4h. Do not exceed 5 qt/A per year. Apply during fallow intervals, prior to planting, at planting, before crop has emerged, or to row middles with a hooded or shielded sprayer or wiper applicator.

HRAC Group 14:

carfentrazone (Aim EC): 0.5 to 2 fl oz/A; PHI 0d, REI 12h. Do not exceed 6.1 fl oz/A per season. Apply in emerged crops with hooded sprayer. Contact with crop will cause damage.

Weed Control