Kiwifruit

Joe DeFrancesco
Revised March 2014

KIWIFRUIT—Weed and Vegetation Management

General strategy The type of vine support structure and the method of irrigation influence weed management. Shade from pergolas reduces light available for weed germination and growth. A T-bar trellis may facilitate growth of perennial sods or winter cover crops between the kiwi rows for soil conservation. Drip irrigation reduces weed germination and growth within rows and in aisles. Minimize weed competition and interference within rows. (See “Section L: Orchards and Vineyards” in this handbook.)

Cultivation Tillage controls annual weeds while suppressing perennials, depending on tilling frequency (every three weeks as necessary to eventually deplete perennials). Adverse effects include soil erosion from sloping sites, soil compaction, and reduced water infiltration during winter rains (except in very sandy soils).

Mowing or flailing Mowing or flailing grass sods or weedy vegetation in aisles improves trafficability, prevents erosion, and improves soil conditions. Improved turfgrasses, combined with water and fertilizer management for both the crop and sod, offer long-term advantages in soil management.

Herbicides Kiwifruit roots proliferate in undisturbed, competition-free strips, representing a third to half the area depending on moisture availability. New plantings may benefit from nearly vegetation-free conditions during three years of establishment. Choose combinations of practices that act together to achieve your desired level of vegetation management.

KIWIFRUIT—Site Preparation

glyphosate (several products)

Rate Consult labels.

Time Apply to weeds at least 10 days before planting the crop.

Remarks Use highest rate on field bindweed. Rain within 6 hours after application for any weed species may reduce effectiveness.

Caution Do not apply if weeds are under stress from drought, weather, or maturity.

Action in plant Causes ammonium ions to accumulate, disrupting photosynthesis.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted

KIWIFRUIT—New Plantings

fluazifop (Fusilade DX)

Nonbearing crop only

Rate 0.25 to 0.375 lb ai/A (16 to 24 fl oz/A Fusilade DX)

Time Apply to actively growing grasses, or within 7 days after irrigation, as a directed spray with 1% crop oil or 0.25% nonionic surfactant.

Remarks Identify grass weeds and adjust rates depending on susceptibility and stage of growth as label instructs. Results often are erratic on grasses stressed from lack of vigor, drought, high temperature, or low fertility. More mature grasses and quackgrass can be controlled but may require two applications. Annual bluegrass and all fine fescues resist treatment.

Caution Preharvest interval is 1 year. Grazing is prohibited.

Action in plant Inhibits fatty acid production, cell membranes, and new growth.

Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitors

Chemical family Aryloxyphenoxy propionate

isoxaben (Gallery 75DF and Trellis)

Nonbearing crop only

Rate 0.5 to 1.0 ai/A (0.66 to 1.33 lbs/A product), depending on weed species

Time For preemergence control of certain broadleaf weeds, apply to weed-free soil surface.

Remarks Activate herbicide within 21 days, either using shallow cultivation or irrigation with at least 0.5 inch water.

Caution Preharvest interval is 1 year.

Action in plant Appears to disrupt root and hypocotyl development. Susceptible plants die before emerging.

Site of action Group 21: inhibits cell wall synthesis Site B

Chemical family Benzamide

trifluralin + isoxaben (Snapshot)

Nonbearing crop only

Rate 2.5 to 5 lb ai/A (100 to 200 lbs/A Snapshot) depending on weed species

Time For preemergence control of certain broadleaf weeds and grass weeds, apply to weed-free soil surface.

Remarks Activate herbicide within 3 days, either using shallow cultivation or irrigation with at least 0.5 inch water.

Caution Preharvest interval is 1 year.

Action in plant (isoxaben) Appears to disrupt root and hypocotyl development. Susceptible plants die before emerging. (trifluralin) Inhibits mitosis in shoots and roots.

Site of action (isoxaben) Group 21: inhibits cell wall synthesis Site B; (trifluralin) Group 3: microtubule assembly inhibitor

Chemical family (isoxaben) benzamide; (trifluralin) dinitroaniline

napropamide (Devrinol 50-DF)

Rate 4 lb ai/A (8 lbs/A Devrinol 50-DF)

Time Apply after transplanting to firm soil, before weeds germinate.

Remarks Water the day of treatment to wet the soil 2 to 4 inches deep, to reduce degradation by sun and to activate the herbicide. Where convenient, shallow mechanical incorporation appears to improve activity.

Action in plant Inhibits root growth.

Site of action Group 15: inhibits very long chain fatty acid synthesis

Chemical family Acetamide

oryzalin (Surflan A.S. or Oryzalin 4 A.S.)

Rate 2 to 6 lb ai/A (2 to 6 quarts/A product)

Time Apply after transplanting to firm soil, before weeds germinate. Requires sprinkler irrigation, rain, or shallow cultivation (1 to 2 inches) to activate.

Remarks Rate depends on duration of weed control desired.

Caution Do not use on soils with more than 5% organic matter. Avoid exposing transplant roots to contact with treated soil.

Action in plant Inhibits mitosis, primarily in roots.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Dinitroaniline

KIWIFRUIT—Established Plantings—Winter Applications that Persist in Soil

napropamide (Devrinol 50-DF)

Rate 4 lb ai/A (8 lbs/A Devrinol 50-DF)

Time Apply fall through spring, before weeds germinate, or apply foliar-active herbicide to control existing weeds.

Remarks Irrigation or shallow incorporation is recommended following treatments made November through February if no rain falls within 2 weeks of application. If applied March through October, irrigate within 24 hours to wet soil 2 to 4 inches deep. Shallow mechanical incorporation seems to enhance activity. Performance is reduced with excessive plant residue on soil surface.

Caution Do not apply within 35 days of harvest.

Action in plant Inhibits root growth.

Site of action Group 15: inhibits very long chain fatty acid synthesis

Chemical family Acetamide

oryzalin (Surflan A.S. or Oryzalin 4 A.S.)

Rate 2 to 6 lb ai/A (2 to 6 quarts product/A)

Time Apply late fall or early spring to bare soil or after existing vegetation has been destroyed by tillage or by using a foliar-active herbicide.

Remarks For longer residual control use higher rates, or split treatments and apply in fall and spring. Irrigate with at least 0.5 inch of water or rain to activate herbicide. Shallow cultivation can control newly germinated weeds without reducing herbicide activity.

Caution Do not use on soils with more than 5% organic matter. Wait 24 months before planting vegetables after kiwi.

Action in plant Inhibits mitosis, primarily in roots.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Dinitroaniline

KIWIFRUIT—Established Plantings—Directed Applications in Kiwifruit Rows

acetic acid (Weed Pharm)

Rate 15 to 30 gals/A WeedPharm (20% acetic acid)

Remarks Apply as a directed application to actively growing, small weeds. Application equipment must be hooded or shielded. Any contact with the crop will cause crop injury. Weed Pharm can be applied up to and including the day of harvest. Approved for organic production.

Caution This product is a contact, nonselective, herbicide. Avoid contact with desirable kiwi foliage, green bark, or fruit. Wear safety glasses.

carfentrazone (Aim EC or Aim EW)

Rate 0.031 lb ai/A (2 fl oz/A Aim)

Remarks Apply as a directed application to actively growing weeds not beyond the six-leaf stage. Allow at least 14 days between applications. Preharvest interval is 3 days.

Caution This product is a contact, nonselective, broadleaf herbicide. Avoid contact with desirable kiwi foliage, green bark, or fruit.

Action in plant Disrupts cell membranes.

Site of action Group 14: protoporphyrinogen oxidase inhibitor

Chemical family Triazinone

glyphosate (several products)

Rate Spray: consult labels

Remarks Select application equipment to prevent crop injury by directing spray, or use selective applicators. Adjust concentration depending on equipment. See label for rate and application time, especially for perennial weeds. Adding surfactant or mixing ammonium sulfate according to label directions may improve control of slightly stressed weeds.

Caution Do not allow drift or mist to contact green foliage, green bark, suckers, or vines and renewals less than 3 years old. Preharvest interval is 14 days. If applications are repeated, check label for the maximum amount of glyphosate allowed per season.

Action in plant Causes ammonium ions to accumulate, disrupting photosynthesis.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted

glyphosate (several products)

Rate Wiper: 33% solution

Time Mix 1 gal product to 2 gal water, and wipe weeds.

Remarks Avoid contact with desirable vegetation. In severe infestations, reduce equipment ground speed, or apply in two directions to ensure contact with wiper. (See remarks above.)

Caution Do not contact green foliage, green bark, suckers, or vines and renewals less than 3 years old. Preharvest interval is 14 days. If applications are repeated, check label for the maximum amount of glyphosate allowed per season.

Action in plant Causes ammonium ions to accumulate, disrupting photosynthesis.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted

oxyfluorfen (GoalTender or Galigan H2O)

Rate 0.5 to 1.5 lb ai/A (1 to 3 pints/A product)

Time Apply only to healthy vines.

Remarks Direct spray toward base of vines; avoid direct plant contact. Dormant application only; do not apply oxyfluorfen after buds start to swell until harvest is complete. Controls broadleaf weeds preemergence and postemergence, depending on application rate and weed species. For preemergence control of susceptible weeds, use 1.25 to 1.5 lb ai/A on a clean, weed-free soil surface. For postemergence control of susceptible weeds, use 0.5 to 1.5 lb ai/A, depending on stage of growth.

Caution Do not apply to established plants less than 3 years old unless vines are trellised a minimum of 3-ft above soil. Oxyfluorfen can be applied upon completion of final harvest. Do not exceed 1.5 lb ai/A per season.

Action in plant Acts as a contact-type herbicide, either directly on broadleaf weeds or at soil surface as weeds emerge.

Site of action Group 14: protoporphyrinogen oxidase inhibitor

Chemical family Diphenylether

paraquat (Gramoxone, others)

Rate 0.625 to 1.0 lb ai/A (Gramoxone: 2.5 to 4.0 pints/A; Other brands: 1.7 to 2.7 pints/A)

Time Apply as a directed, shielded spray toward base of vines when weeds are growing vigorously and new weeds are 1 to 6 inches high.

Remarks Add a nonionic surfactant or crop oil concentrate according to label; avoid anionic formulations that react in the tank to form insoluble precipitates.

Caution A restricted-use pesticide. Do not ingest or inhale spray mist. Wear protective face shields, respirators, and clothing. Do not let spray contact green stem, fruit, or foliage. Avoid windy conditions. Do not treat more than three times per year. Preharvest interval is 14 days.

Action in plant Acts as contact; absorbs energy produced during photosynthesis and forms peroxides that disrupt living cells.

Site of action Group 22: photosystem I electron diversion

Chemical family Bipyridilium

pelargonic acid (Scythe)

Rate For annual weeds, a 3% to 5% solution; for perennial herbaceous weeds and sucker control, a 5 to 7% solution.

Remarks Apply in 75- to 200-gal/A water broadcast; agitation is required. Cool weather may slow the product’s activity, and delay or reduce visible effects. This product is a contact, nonselective herbicide and controls only actively growing, emerged green vegetation.

Action in plant Control or burndown of a broad spectrum of weeds on contact.

Site of action Group 26: unknown

Chemical family Carboxylic acid

pyraflufen (Venue)

Rate 0.001 to 0.005 lb ai/A (1 to 4 oz/A Venue)

Remarks Apply as a directed application to actively growing weeds less than 4 inches high, or rosettes less than 3 inches in diameter. Use lower rate for small weeds and higher rate for larger weeds. Do not exceed 6.8 fl oz/A or three applications per season. Allow at least 30 days between applications. Apply only at pre-bloom or postharvest, or during dormancy. Mixing this herbicide with another herbicide increases the weed spectrum and is highly recommended.

Caution This product is a contact, nonselective, broadleaf herbicide. Avoid contact with desirable kiwi foliage, green bark, or fruit. Do not exceed 6.8 oz/A Venue per season.

Action in plant Inhibits protoporphyrinogen oxidase (PPO) that disrupts cell membranes.

Site of action Group 14: protoporphyrinogen oxidase inhibitor

Chemical family Phenylpyrazole