Vegetable Production Guide

Lettuce
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Table 3 Lettuce Disease Control

This section was updated - 12 September 2018

Table 3 Lettuce Disease Control

 

Product

Rate

PHI*

Comments

Drop (White Mould)

Lance WDG

(boscalid)

Group 7

385 g/ha
(154 g/acre)

Apply in 100 L/ha (40 L/acre) of water
14
  • Suppression only.
  • Direct-seeded: Apply 1 to 2 days after thinning. If required apply 10 to 20 days later.
  • Transplanted: Apply 7 to 10 days after transplanting. If required, apply 10 to 20 days later.
  • Do not apply more than 2 times per season.
  • Do not enter treated for 12 hours.
  • For crops not on the label, observe a plant back interval of 14 days.

Cantus WDG

(boscalid)

Group 7

Sercadis

(fluxapyroxad)

Group 7

250 to 333 mL/ha
(101 to 135 mL/acre)

Apply in 100 L/ha (40 L/acre) of water
1
  • Suppression only.
  • Repeat at 7 to 14 day intervals.
  • Do not make more than 3 applications per season.
  • Do not apply more than 1.0 L/ha (405 mL/acre) per season
  • No more than 2 consecutive applications before alternating with a fungicide with a different mode of action.
  • Do not enter treated area for 12 hours.
  • For crops not listed, observe a plant back interval of 1 year.

Isofetamid 400SC

(isofetamid)

0.90 L/ha
(0.37 L/acre)

 

14
  • For water volume, see label details.
  • Direct seeded:  make the 1st application after emergence or thinning.
  • Transplanted lettuce:  make the 1st application immediately after transplanting.
  • Repeat at a 14 day interval.
  • Do not make more than 2 applications per year.
  • Observe a plantback interval of 30 days for crops not listed.
  • Do not re-enter treated area for 12 hours.
  • Group 7 fungicides.

Kenja 400SC

(isofetamid)

Serenade Opti

(Bacillus subtilis)

smileyUsed in organics

0.6 to 1.7 kg/ha
(240 to 690 g/acre)
0
  • Suppression only.
  • Make first application at planting or immediately following planting, but prior to crop emergence.
  • Make second application within 7 days of thinning, with a directed spray to ensure thorough coverage of lower leaves and surrounding soil surface,.
  • Repeat using a 10 to 14 day interval.
  • Also suppresses grey mould and downey mildew.  See Grey Mould and Downey Mildew sections of this table.
  • smileySerenade Opti and Serenade Max (PCP# 31666, 28549) are OMRI-Canada listed.  Check with your certification body before using in an organic operation.

Serenade Max

(Bacillus subtilis)
 
Note:  no longer produced.
 
smileyUsed in organics

 

1.0 to 3.0 kg/ha
(0.4 to 1.2 kg/acre)

Double Nickel 55

(Bacillus amyloliqufaciens strain D747)

1 to 2.5 kg/ha
(400 to 1000 g/acre)

For smaller plants or low disease pressure:  0.2 to 1 kg/ha (80 to 400 g/acre)

0
  • Suppression only.
  • Apply as a foliar spray to head formation.
  • Repeat at 3 to 10 day intervals.
  • Do not use highly alkaline or highly acidic water to mix sprays.
  • If necessary, use a buffering agent to maintain a pH of 6 to 8 in the water of the tank. 
  • Do not re-enter treated area for 4 hours
  • Group 44 fungicides.
  • Also suppresses downy mildew.  See Downy Mildew section of this table.

Double Nickel LC

(Bacillus amyloliqufaciens strain D747)

5 to 12.5 L/ha
(2 to 5.0 L/acre)

For smaller plants or low disease pressure:   1 to 5 L/ha ( 0.4 to 2 L/acre)

Downy Mildew

Ridomil Gold MZ 68WP

(metalaxyl-M/mancozeb)

Group 4M

2.5 kg/ha
(1.0 kg/acre)
14
  • FOR USE ON HEAD LETTUCE ONLY.
  • Apply every 14 days beginning at thinning for a maximum of 3 applications per crop.
  • While it is highly effective against susceptible isolates of the fungus, resistance builds up rapidly and has already been identified in Cloverdale.
  • Do not use on soils with less than 2 percent organic matter or in areas where the water table may be high.
  • Must be applied before the outbreak of the disease.
  • Do not enter treated area for 24. hours.

Diplomat 5SC /    Polyoxin D Zinc 5SC

(polyoxin D zinc salt)
 
Group 19
463 to 926 mL/ha
(187 to 375 mL/acre)
0
  • Suppression only.
  • Repeat using a 7 to 14 day interval.
  • Do not apply more than 2.8 L/ha (1.1 L/acre) per season or 12 months.
  • May be used in the greenhouse.

Torrent

(cyazofamid)
Group 21
0.2 L/ha
(80 mL /acre)

Apply in 200 to 500 L/ha (80 to 200 L/acre) of water
0
  • Suppression only.
  • Apply as a foliar broadcast or spray directed at the base of the plant.
  • Repeat using a 7 to 14 day interval.
  • Do not apply more than 6 times per crop per year.
  • Tankmix with a non-ionic or organosilicone surfactant such as Sylgard 309 at the manufacturer's label recommendations.
  • Observe a plantback interval of 30 days for crops not listed.
  • Do not enter treated area for 12 hours.
  • Also controls Pythium Root Rot and Pythium Damping Off when applied as a soil drench to greenhouse transplants.  See Pythium Root Rot section of this table for details.

 

Orondis

(oxathiapiprolin)

Group 49

75 to 350 mL/ha (70 to 140 mL/acre

Apply in 110 L/ha (45 L/acre) of water.

0
  • Repeat at 5 to 14 day intervals.
  • Where multiple crop cycles are produced in the same year, do not make more than 6 applications/ha/year.
  • Do not apply more than 1.40 L/ha (570 mL/acre) per season.
  • Do not re-enter treated area for 12 hours.

Phostrol

(mono- and dibasic sodium, potassium, and ammonium phosphites)

 

Group 33

2.9 to 5.8 L/ha (1.2 to 2.3 L/acre)

Apply in 225 L/ha (90 L/acre) of water

0
  • Repeat at 7 to 14 day intervals.
  • Do not make more than 7 applications per season.
  • Do not re-enter treated area for 12 hours.

Confine Extra        

(mono- and di-potassium salts of phosphorous acid)

Group 33

3 to 7 L/ha
(1.2 to 2.8 L  /acre)

Apply in 100 L/ha (40 L/acre) of water.

1
  • Suppression only.
  • Repeat using a 7 to 14 day interval.
  • Do not make more than 6 applications per growing season.
  • Tankmixing with pesticide products containing a metal base and/or micronutrients may not be compatible and could potentially cause plant injury.  See label for details.
  • Also suppresses Bacterial Leaf Spot (Xanthomonas campestris pv. vitians) in leaf lettuce - at the high rate and using a 7 day application interval.  

Aliette WDG

(fosetyl-aluminum)

Group 33

2.8 kg/ha
(1.1 L/acre)
7
  • Apply in 150 L/ha (60 L/acre) of water.
  • Do not make more than 5 applications per year.
  • Do not enter treated areas for 12 hours.

Revus

(mandipropamid)

Group 40

400 to 600 mL/ha
(160 to 240 mL/acre )

Apply in 100 L/ha (40 L/acre) of water
1
  • Use a non-ionic adjuvant (0.125% v/v).
  • Repeat at 7 to 10 day intervals.
  • Do not apply more than 4 times per year.
  • Do not apply to greenhouse-grown seedlings to be transplanted in the field, until after they have been transplanted out.
  • Do not enter treated area for 12 hours.

Forum

(dimethomorph)
 
Group 40

 

450 mL/ha (182 mL/acre)

Apply in 200 L/ha (80 L/acre) of water.

0
  • Suppression only.
  • Tankmix with another fungicide active against downy mildew.
  • Repeat at 5 to 10 day spray intervals.
  • Do not make more than 5 applications per season.
  • Do not re-enter for 2 days for hand-harvesting and for all other activities do not re-enter for 12 hours.
 

Zampro

(ametoctradin & dimethomorph)

Group 40 & 45

1.0 L/ha
(400 mL  /acre)

Apply in 200 L/ha (80 L/acre) of water.
0
  • Repeat at 5 to 7 day intervals.
  • Do not apply more than 3 times per season.
  • Do not apply with adjuvant.
  • Do not re-enter for hand-harvesting for 1 day.  For all other activities do no enter treated area for 12 hours.
  • Do not use in greenhouses.

Presidio

(fluopicolide)

Group 43

220 to 292 mL/ha
(89 to 118 mL/acre)

Apply in 200 to 1000 L/ha
(80 to 405 L/acre) of water
2
  • Tank-mix with a product that has a different group number listed in this table for downy mildew, such as Aliette.
  • Follow most restrictive directions including rate, PHI and re-entry interval.
  • Repeat using a 7 to 10 day interval.
  • Do not apply more than 4 times per season.
  • Maximum of 880 mL/ha (356 mL/acre) per season.
  • Do not enter treated for 12 hours.

Double Nickel 55

(Bacillus amyloliqufaciens strain D747)

1 to 2.5 kg/ha
(400 to 1000 g/acre)
0
  • Suppression only.
  • Repeat at 7 to 10 day intervals.
  • Do not use highly alkaline or highly acidic water to mix sprays.
  • If necessary, use a buffering agent to maintain a pH of 6 to 8 in the water of the tank. 
  • Do not re-enter treated area for 4 hours.
  • Group 44 fungicides.
  • Also suppresses drop (white mould).  See Drop (White Mould) section of this table.

Double Nickel LC

(Bacillus amyloliqufaciens strain D747)

5 to 12.5 L/ha
(2 to 5.1 L/acre)

Serenade Opti

(Bacillus subtilis)
smileyUsed in organics
1.7 to 3.3 kg/ha
( 690 to 1300 g/acre)
0
  • Suppression only.
  • Repeat at 7 to 10 day intervals.
  • Also suppresses drop (white mould) and grey mould rot.  See Drop (White Mould) and Grey Mould Rot sections of this table.
  • smileySerenade Opti and Serenade Max (PCP# 31666, 28549) are OMRI-Canada listed.  Check with your certification body before using in an organic operation.

Serenade Max

(Bacillus subtilis)
 
Note: no longer produced.
 
smileyUsed in organics
3.0 to 6.0 kg/ha
(1.2 to 2.4 kg/acre)

Grey Mould Rot

Botector

(Aureobasidium pullulans DSM 14940 & DSM 14941)
1 kg/ha
(0.4 kg/acre)

Apply in 500 to 2000 L/ha (200 to 800 L/acre) water
0
  • Suppression only.
  • May be used in the greenhouse.
  • Apply soon after emergence or transplant.
  • Repeat applications using a 7 day interval.
  • Spray plants to run-off.
  • Keep water temperature below 25ºC.
  • Apply in the morning or evening hours and during cool temperatures.
  • Do not allow mixed spray solution to stand overnight or for more than 8 hours. 
  • Do not re-enter treated area for 4 hours,

Rovral WP

(iprodione)

Note:  Registration cancelled.  Last date of use for remaining stocks is June 21, 2021

Group 2

1.5 kg/ha
(0.6 kg/acre)

Apply in 300 to 500 L/ha (120 to 200 L/acre) water
4
  • Do not apply more than 4 times per year.
  • Ensure a 7 day interval between sprays.
  • Recommended only for unusually severe conditions when serious grey mould problems are anticipated.
  • Do not enter treated area for 12 hours.

Lance WDG

(boscalid)

Group 7

285 g/ha
(114 g/acre)

Apply in 100 L/ha (40 L/acre) of water
14
  • Direct-seeded: Apply 1 to 2 days after thinning. If required apply again 10 to 20 days later.
  • Transplanted: Apply 7 to 10 days after transplanting. If required, apply again 10 to 20 days later.
  • Do not apply more than 2 times per year.
  • Do not enter treated area for 12 hours.
  • For crops not on the label, observe plant back interval of 14 days.

Cantus WDG

(boscalid)

Group 7

Serenade Opti

(Bacillus subtilis)

0.6 to 1.7 kg/ha
(240 to 690 g/acre)
0
  • Suppression only.
  • Repeat at 7 to 10 intervals.
  • Note:  Serenade Max is no longer produce.
  • ☺ Approved for use in organics.
  • Also suppresses drop (white mould) and downey mildew.  See Drop (White Mould) and Downey Mildew sections of this table.

Serenade Max

(Bacillus subtilis)

1.0 to 3.0 kg/ha
(0.4 to 1.2 kg/acre)

Fontelis

(penthiopyrad)

Group 7

1.25 to 1.75 L/ha
(500 to 710 mL/acre)

Apply in 110 L/ha (45 L/acre) of water
3
  • Also suppresses Sclerotinia drop.
  • Repeat at 7 to 10 day intervals.
  • Do not apply more than 5.25 L/ha (2.2 L/acre) per season.
  • Do not make more than 2 sequential applications before switching to a fungicide with a different mode of action.
  • Do not re-enter for 12 hours.

Pythium Root Rot (Pythium spp.)

Torrent

(cyazofamid)
 
Group 21
30 mL/100L water 40
  • REGISTERED ON GREENHOUSE LETTUCE TRANSPLANTS.
  • Also controls Pythium Damping Off.
  • Apply once in the greenhouse as a soil drench to thoroughly wet the growing medium immediately after seeding.
  • Do not use a surfactant.
  • Do not enter treated area for 12 hours.
  • Also suppresses downy mildew when applied as a foliar spray in field lettuce.  See Downy Mildew section of this table.

 

Serenade Soil

(QST 713 strain of dried Bacillus subtilis)
 
smileyUsed in organics.

 

2.7 to 14 L/ha (1.1 to 5.7 L/acre) 0
  • Suppression only.
  • Also suppresses Rhizoctonia damping-off. 
  • smileySerenade Soil (PCP# 30647) is OMRI-Canada listed.  Check with your certification body before using in an organic operation.

Transplant drench:

  • Apply as a drench at the time of transplanting.
  • Apply at a rate to thoroughly soak the growing media through the root zone or asa drench or directed spray using sufficient water to soak the root zone.

Post-plant applications:

  • Additional applications may be made to the soil as a drench or spray directed towards the base of the plant.
  • Irrigate to move material into the seed, root or transplant zone within 24 hours.
  • Repeat at 21 to 28 day intervals.

Bottom Rot (Rhizoctonia solani)

Taegro

(Bacillus subtilis)
 
smileyUsed in organics.

190 g/ha (77 g/acre)

Apply in 935.4 L/ha (378.6 L/acre) of water

0
  • Suppression only.
  • Apply to the plant base and soil/growing medium surface to protect the contact between soil and leaf tissue.
  • Water-in product after applying.
  • Repeat at 7 day intervals.
  • smileyTaegro (PCP# 30720) is OMRI-Canada listed.  Check with your certification body before using in an organic operation.
*PHI = Pre-harvest interval.
BUFFERS – Refer to product label for buffer requirements. See also Pesticide Regulations and Safety section of this guide.
PESTICIDE GROUP DETAILS – see Pesticide Toxicity Table of this guide.
smileyOMRI-Canada = Organic Materials Review Institute of Canada

 

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