Mansfield Grower Program

Author Erfan VafaiePosted on June 17, 2019June 17, 2019Categories General, Growers, Integrated Pest Management, Notes

This week, one of our Texas growers held an internal full-day training program and were kind enough to allow me to take notes and share them with the rest of you growers! One of the many things I continue to really appreciate and like about the green industry in Texas: they are collaborative and help each other out. See below for speakers and notes related to their presentations.

Please note that I do not personally endorse the products mentioned by the presenters below – the notes provided below are “as-is”, as written as accurately I could based on the information provided by the presenters. Any lack of information or misinformation is not intentional.

Dr. Ann Chase – Recognizing plant diseases and how to manage them.

Dr. Ann Chase – Common diseases of poinsettias.

Dr. Raymond Cloyd – How to deal with mite pests in horticultural production systems.

Dr. Raymond Cloyd – Thrips management.

Gary Volmer – Best Practices and 2018 season challenges with poinsettia production

Recognizing plant diseases and how to manage them

Dr. Ann Chase
Chase Agricultural Consulting

Dr. Chase was kind enough to provide her presentation to share. The presentation contains several images of plant pathogen symptoms that are invaluable – thank you Dr. Chase! The presentation is a bit large, so I split it into three (a, b, and c) PDF files below.

Grower2019 training_a
Grower2019 training_b
Grower2019 training_c

• Not everything is a disease
• Cold water, cold temps, etc. can cause disease-like symptoms in some situations

• Felicia, Gaillardia, Osteospermum, Helianthus
• Red salvia, blue salvia, Coleus
• Snapdragon, Linaria
• Pansy, Viola
• Lettuce, Osteospermum
• Delphinium, Larkspur
• Rose, raspberry
• Kale, Iberis, Alyssum, Broccoli, Erysium, stock, cabbage

• Often looks like a burn on the upper side of the leaves. Sucking moisture out of the leaf. Look underneath for the spores
• Crinkly leaves, especially on snapdragons, can be a sign of downy mildew. If there are no aphids or other sucking insects, it may be downy
• On Impatiens, can get grey, lavender, white, or purple. Black on basil.

• Segovis worked really well.
• Be sure to rotate to prevent resistance!

• Compass O, Heritage (11-strobilurins) OR FenStop (11-non-strobilurin) OR any 7-11
• Subdue MAXX (4-mefenoxam/tank-mix as directed)
• Adorn (43-fluopicolide/tank-mix as directed)
• Aliette (33-phosphonate) and many others
• Segway-O (21-cyazofamid)
• Micora
• Segovis will last a good month – spray preventatively on any plants that get downy mildew
• • then watch the weather closely! Segovis will give 1-month protection, then keep an eye on the weather and plants for need for future sprays.
• FenStop is going away in about a year – won’t be registered for use.

• must still be aware of potential for downy infection and be ready to treat as needed
• resistant-line does help reduce downy damage, but does not mean they won’t get the disease

• can starts as a small spot (brown) on underside of leaves
• can look like spray damage or anthracnose.
• if petiole is going (dark) and starting to work into leaves in cuttings, that can be botrytis.

• spray them at that time!

• spores form on all parts of the plant
• Botrytis spores spread by fans or wind and infect new leaves
• spores and sporangiophores of Botrytis. Overnight moisture on leaves is especially favorable for Botrytis sporulation

• environmental factors inducing development of fungal spores
• • Exactly the same as what the plant needs
  • Botrytis optimal temperature are 75 – 82 F
  • grows at 32 – 95F
  • spores have lasted as long as 14 months under dry conditions
• KleenGrow is a different category as the other quartenary ammoniums, safer to plants, doesn’t degrade as quickly and has longevity – good for cleaning between crop cycles

• Heat and vent at dusk to reduce humidity
• space plants on the bench to reduce humidity
• All handling can spread Botrytis spores, including irrigation and fingicide spraying
• Never water at night!

• Works incredibly well on Hydrangea or pansy flowers

• Didn’t work at all on Botrytis petal blight on pansy
• Broadform worked quite well
• Phytotoxicity
  • • Saw phyto on the flower edges, but went away by third application
    • A combination of temperature, water, and the fungicide – not able to repeat it.

• mainly see it when the seasons are shifting. Will go from botrytis to sclerotinia
• around late March-early April
• Astun was the only product that worked on geranium!
  • • Which fungicide worked depended greatly on the plant it was on.

1. Medallion or Palladium
2. Astun, Broadform or Orkestra Intrinsic

• Pageant intrinsic
• Heritage (2-4 oz)
• Palladium

• Control the thrips or throw out plants infected with it.

• Sells a product that can detect several viruses
• TMV, STWV, INSV, CMV
• Plant may ‘appear’ to have cured the virus if new leaves come out that are asymptomatic
• • plant still has the virus! Several factors can influence whether symptoms show or not
  • virus is non-evenly distributed throughout the plant

• BotryStop & Kalmor, work really well
• Copper works really well
• Mancozeb also work well (but can have bad residue)
• Biologicals Bacillus based on biologicals like Cease, Stargus, and Triathlon
• DDAC – KleenGrow

• Segovis worked 100%

Common Diseases on Poinsettias

Dr. Ann Chase
Chase Agricultural Consulting

Dr. Chase was kind enough to provide her presentation to share. The presentation contains several images of plant pathogen symptoms that are invaluable – thank you Dr. Chase!

Full PDF Presentation: poinsettia 2019_grower

• Large list of of common poinsettia diseases
• Most likely thing to see; Botryitis in propagation
• Erwinia
  • • mostly an issue when over-irrigating
• ‘Direct’ sticking eliminates a lot of these disease issues

• Chipco 26019 NG, 26019 FLO
• Daconil Ultrex
• Decree
• Astun, Broadform, and Orkestra intrinsic

• often occurs early in the crop, and not late
• Likes hot weather
• Can see some mycellium (white stuff) on the outside
• Does not happen when you are sleeving them and taking them out the door! That’s botrytis

• 3336, Fungo, OHP numbered product
• heritage
• medallion
• Mural, Pageant intrinsic
• Rootshield or rootshield plus
• • Works great when you first transplant, and covers pythium, phytopthora and rhizoctonia for first 8 weeks

• If one of the cuttings in the pot dies
• Loves swimming in ebb and flow floor!
• Can potentially get pythrium growing all the way up the stem of the plant

• Segway O
• RootShield Plus
• Empress Intrinsic
• Subdue MAXX, consider adding KleenGrow for aid in resistance management
• Terozole and truban

• might be isolated to specific cultivars

• Compass, Disarm O, Heritage, Mural or Pageant Intrinsic
• MilStop (higher labelled rate will cause significant residue!)
• Palladium (preventative, the 4 oz rate)
• Terraguard, Eagle, and many others

• Agri-Mycin
• Copper (Camelot-O, little residue! Kalmor; Kocide 3000; and Phyton 27)
• KleenGrow
• Triathlon BA or Cease
• EcoSwing

• Adorn
• Segway O
• Segovis
• Subdue MAXX
• Stature SC or Orvego OR Micora

•  Identified in Oklahoma State University
• Going to try fusarium treatments and see how well it works

How to deal with mite pests in horticultural production systems

Dr. Raymond Cloyd
Kansas State University

• Twospotted spider mites
• Broad mites
• Cyclamen mites

• feed on chlorophyll content
• prefer dry warmer climates

• do not feed in the vascular tissue
• feed on the chloroplasts
• that’s why we won’t really have systemic activity on mites

• eggs -> larvae (six legged) -> protonymph (eight-legged) -> deutonymph -> adult

• avoid over fertilizing plants with nitrogen-based fertilizers
• remove old plant material that can serve as a source of spider mite populations
• do not allow plants to experience water stress
• Remove weeds and heavily-infested plants within and around the area
• • nightshade plants tend to be major magnets of spider mites (tomatoes, peppers, etc.)
• Overhead irrigation, especially in propagation and outdoor production areas, can reduce spider mite infestations

• Abamectin (Avid)*
• Bifenazate (Floramite)
• Bifenthrin (Talstar)
• Chlorfenapyr (Pylon)*
• Clofentezine (Novato)
• Etoxasole (TetraSan)*
• Fenpyroximate (Akari)
• Hexythiazox (Hexygon)
• Petroleum, mineral, and neem-based oils
• Potassium salts of fatty acids (insecticidal soaps)
• Spiromesifen (Savate)*
• Spirotetramat (Kontos)* – only systemic miticide, but needs to be applied very early

• ’selection pressure’ for resistance increases as application frequency increases.
• example of how resistance can develop in a mite population provided
• due to the fact that mites cannot fly, genetic mixing does not occur as much, thus resistance can become fixed quicker than an insect/population that has influxes of non-resistant populations

• short generation time
• high number of generations (over 50 within a growing season)
• high reproductive rate
• broad host range

• pesticides that are active on specific target sites such as the central nervous system or enzymes associated with metabolism

• target more general physiological/biological targets, affecting a wide range of insects

• surfactants, stickers, etc.
• can help break the surface tension of the water and allow the miticide to spread better & contact the mites.

• Been around since the 1970s
• Phytoseiulus persimilis, A. californicus, A. fallacis, G. occidentalis, A. andersoni

• P. persimilis does not do very well in warm (+80F) or dry environments

• size: 1/100 inch long
• eggs have bumps
• require high relative humidity (>80%) and temperatures around 60F
• Do not produce webbing

• causes the leaf to curl
• cause leaf distortion
• leaves curling downwards on sage
  • • almost looks like they weren’t watered

• Abamectin
• Chlorfenapyr
• Fenpyroximate
• Pyridaben
• Spiromesifen
• Spirotetramat

• several predatory mites for controlling broad mites

Thrips Management

Dr. Raymond Cloyd
Kansas State University

• Abamectin (Avid)
• Acephate (Orthene)
• Bifenthrin (Talster)
• Chlorfenapyr (Pylon)
• Kinoprene
• Methiocarb
• Novaluron
• Pyridalyl
• Spinosad

• pest identification
• coverage and timing
• water quality
• rotating modes of action
• etc.

• tried ancora and drenches of distance, and some other products. No efficacy

• gives a better idea of how good or poor the spray coverage is

• What is pH?
• • measurement of the concentration of hydrogen ions in a solution
• When pH of the spray solution is >7.0, then certain insecticides may be susceptible to alkaline hydrolysis
• • degrades or fragments the active ingredient
  • Organophosphates are very sensitive to alkaline hydrolysis
• Extension publication that provides a range for pH range for different active ingredients
• In general, pH between 5.5 to 6.8 is safe zone for most commercially available active ingredients

• number of predatory mites, predatory bugs, beneficial fungi, and entomopathogenic nematode
• Not all stages of thrips are susceptible to attack by beneficial arthropods

• great predators of fungus gnat larvae
• also predators of western flower thrips pupae

• has information on the area of screening needed to prevent movement of air flow from the greenhouse fans. PDF Publication from NGMA

Best Practices and 2018 season challenges with poinsettia production

Gary Volmer, Ball Seed Company

• disinfest or clean all surfaces in cutting handling areas and propagation areas
• • helps manage erwinia, if it pops up
• worker hand sanitation
• foot baths entering the propagation area
• Disinfect all surfaces!

• open boxes quickly and stick or cool cuttings (not below 50 degrees!)
• keep cuttings moist and turgid while handling
• unpacking in a cooler 50F (10C) is ideal… not colder!
• avoid cuttings getting hot during handling
• if cuttings arrive warm, open bag, moisten, and cool overnight at 50F (10C)
• do not store cuttings in boxes in warehouse or greenhouse conditions
• • If you are starting to stick a cutting thats already wilting, its really hard to get them back
• Place cuttings on a tray & mist before putting in the cool, ideally! If you can’t get them on trays in misted, then at least put them in the cooler overnight with the box opened. Opening box allows the cool to actually penetrate and get the bad gases out (i.e. ethylene). If the box is still cool (use infrared thermometer), keep the box sealed and store them that way.
• • Only have as many cuttings outside as you can stick in 30 minutes! Keep the rest in the cooler and bring more out as needed

• Loose-filled liner trays
• • pick right media, no plug mixes!
  • coarse roots result in media “fall out”
• stabilized media
• direct stick
• •  Before direct stick, most the soil so that the soil has enough structure for the cutting to stay upright. Do not put too much water (i.e. watering to bottom of the pot)!

• shade greenhouse to lower light levels during to <2,000FC
• soil temperature at 68 – 72F; Air temp 65 – 80F
• maintain high relative humidity >80%, especially first 4-5 days
• Keep concrete floors wet to help maintain humidity!
• • Especially in larger structures where maintaining high humidity is difficult
  • Only need enough moisture applied to the leaves to keep the leaves moist, but apply rest of the water elsewhere just to maintain that high humidity.
• minimize air movement but vent as needed to keep temps below 85F
• Start to pull mist back around days 5-7 as cuttings start to callus; start with night mist and early mornings.

• Minimize pooling on leaves
• if using overhead misters, cycle on for shortest time possible
• Leaf starts to appear a bit translucent
• If using booms, fast speed to apply only enough moisture glisten the foliage. booms can spread pathogens
• Angle nozzles horizontally
• Utilize CapSil or other foliar wetting agent to make mist more efficient (1/2 label rate or lower)

• Heavy leaching from propagation = little or no media EC at time of root development
• build media EC back up by day 5-7 but be careful not to saturate soil
• Foliar fertilization can help
• • use 50-100 ppm N with a lower or phosphorous-free fertilizer. Phosphorous can cause phyto

• Be careful not to get the IBA up the stem.

• best way to judge your mist
• if it’s one large white ball at the bottom – too much mist! You’re basically telling your cutting that it doesn’t need to root

• begin fertilization program in earnest
• moisture management is crucial in this stage
• Reduce mist to force root growth. Don’t overmist!
• visible roots by day 10
• off mist completely by day 14
• If leaves start to ‘roll’, then you’ve gone too far with misting
• • pay attention to when leaves just start to ‘bend’ down, that’s a sign of when to start misting again. Using this method can help with timing of misting
• If you mist based on the driest part of the greenhouse, you’ll likely be overwatering the rest of the greenhouse. Best to mist based on most watered poinsettias, and then hand water/mist areas that dry out quicker

• crucial that we quickly build media EC back up in this stage
• be carefuly not to fully saturate the soil when fertilizing in the early rooting stage
• Allow soil moisture to dry.
• Start needing phosphorous at this point! Can start getting phosphorous deficiency
• • Lower leaves are yellow and starting to get spots/blotches. Poinsettias will stop growing at this point until you get phosphorous in there.
  • Too much phosphorous or directly on the leaves can damage the tip and other parts of the leaves.

• single application of 300 ppm phosphorous

• sprays of cycocel of B-9/Cycocel tank mix are recommeneded for the last week/weeks of propagation.
• Want to “stack the nodes”
• shorter internodes at pinch enhance branching
• shorter internodes at pinch produce more even branching

• plant into moist media
• irrigate to make sure that the rooting media is moist, not just the media in the finished container. This is more of a challenge with Oasis or other foam media than others
• Maintain this irrigation level until the roots are growing freely into the pot
• Shade and elevated humidity can help reduce the transplant shock

• high porous potting plant media pH adjusted with limestone
• must keep pH lower than 6.6 in media
• Wood fiber, coir issues on pH and calcium nutrition and moisture?
• • as non-peat based components replace peat, so changes the chemical and physical structure of the media
  • less lime in media as wood fiber or coir are less acidic than peat. Observe and manage pH and Calcium levels
  • irrigation practice need to be adjusted as well

• tends to dry near the top of the pot first
• Need to pick up the pot and feel the weight to know whether it is actually drying out or not

• Maintain a media pH of 5.7 – 6.3
• Poinsettia should be grown with a constant liquid feed program of 200 – 250 ppm N
• CalMag feed is recommended as they need a good source of Calcium

• Maintain a media EC of 1.5-2.0 from a pour-through or 0.9-1.3 for a 1:2.
• A healthy and active growing poinsettia will consume a lot of fertilizer
• • if consistently fertilizing and media EC is still low, that is ok Modern Poinsettia will aggressively uptake nutrition
  • Utilize tissue and analysis to ensure nutrition is adequate
• Don’t forget the Moly!

• Below the turning bract
• mottling look on the leaf, edges mottling and turning more yellow
• Typically don’t have this problem if you are watching your media pH

• Yellowing leaves, feed me nitrogen! Especially on younger growing leaves

• “bear paw”, edges of the leaves folding down, can get some latex exuding out
• High humidity & high temperature situations
• Calcium can be applied to foliage to help alleviate this issue

• will actively take these compounds out of the media at low pH
• Iron toxicity, yellow edges of leaves, slight tip curling

• Does not occur frequently, but if it does, it destroys the growing tip

• Florel application prior and post-pinch
• • Not needed on a lot of cultivars
  • Applications of Florel 5 days prior and 5 days after the pinch is a technique that has been used to help ensure good branching in varieties and conditions where branching can be inhibited
• Can cause a “PGR effect” that will continue through the crop cycle
• Rates from 200 ppm to 400 ppm
• Not necessary on many new very free branching varieties

• application of PGR (cycocel) in late propagation
• Pinch on time!
• Don’t leaves too many leaves. Know your specs!
• • this can caues wide plants and smaller bracts
• The growing environment just prior to through to two weeks after pinch is critical
• High humidity is needed to develop the branching evenly
• • misting, quick boom passes, wetting floors, etc. are all useful to maintain higher humidity

• Ecke manual used to suggest a hard pinch with only the spread leaves out
• Now leave 6 – 7 leaves, between hard and soft pinch. Don’t wait to pinch too late (pinch about 13 days after potting up)
• 7 days after pinch, start getting dominant branches from the base
• • Take those dominant branches off! They will outcompete the other branches and cause problems.
• Old school 21 days before pinch, waiting till roots are at the edge of the pot is old strategy! Do not use this method, it will cause grief.

• Cycocel 500 – 1000 ppm spray for cooler regions
• B-9 1000 ppm/Cycocel 500 ppm can be used in warmer climates
• PGR can be applied after the pinch when branches are 1 inch in length or longer
• After pinching the use of PGR of cycocel spray and or B9/Cycocel spray are preferred as they will focus their response

• spray vs drench
• use only spray until shoots are 5 cm (2 in/) in length
• B-nine/cycocel tank mix spray 1,000/750 – Do NOT apply B-9 to a poinsettia in October! Apply before Oct. 1st.
• Cycocel spray 1000-1,500 ppm
• Stop PGR applications by Oct. 10 except for micro drenches of paclobutrazol (bonzi)

• micro drench very low rate! 1/20th ppm – 1/8th ppm
• 1 fl oz / 1 inch pot diameter… 6 oz per 6 in pot
• only apply drench after breaks are established and even. Use Cycocel and/or B-nine/cycocel sprays early
• Late PGR for shelf life improvement: Paclobutrazol (Bonzi) drench of 1-2 ppm at full color ready to sell at first pollen
• Maintain some plants ‘outside’ of your PGR application for comparative purposes, to know whether the PGR is actually working.

• Good roots = good shoots!
• Moisture management is a key driver
• When water stressed then overwatered, can cause pythium!
• • Also trigged by fungus gnats feeding early, bank on pythium later in the season
  • Cut the roots open early (if you have fungus gnats) – if you see some fungus gnat larvae in the roots early on, that’s going to cause problems later when the poinsettia appears established

• do not overhead water late in the day – that’s just begging for disease!

• Talking emitters that regulate how much comes out, so that you have some consistency in water coming out.

• Rhizoctonia
• • early season disease
  • Attacks at or just above the soil line
  • often misdiagnosed as pythium
  • rootshield WP/rootshield plus
  • actinovate
  • cleary’s 3336
  • medallion
  • Heritage/Empress
• Botrytis
• • can attack pre-space when canopy is closed
  • usually starts with leaves but in a closed microenvironment can attack stems
  • No great truly systemic botrytis control!
  • Cease
  • Phyton 27
  • Pageant
  • Palladium
  • Medallion
  • Decree
  • Cleary’s 3336
• Pythium
• • often follows fungus gnat infestations
  • avoid cycling moisture from wet to dry
  • sloughing roots
  • rootshield/rootshield plus
  • Subdue MAXX (watch resistance!)
  • Segway
  • Terrazole/Truban
  • Heritage
  • Aliette
• Powdery Mildew
• • Can attack pre-space when canopy is closed
  • see more every year

• Starts early – results in pythium late
• Larvae feed on roots and Callus
• Vector of pythium?
• Best control is sanitation
• IGR insecticides early

• greenhouse whitefly
• Bemisia tabaci/sweet potato whitefly/silver leaf
• • Q and B-type
• Banded wing whitefly southwest US, Ontario
• scout, scout, scout, scout!
• Use traps!
• Find hotspots
• Outside pressure?
• Biocontrol?
• Non-neonic?

• Temperatures
• • average daily temperatures (ADT)
  • DIF or the relationship between day and night temperatures
• Light
• • light intensity
  • daylength
• Humidity

• Day temps: ideally 24C (75F) to 30C (86F)
• night temps: 16C (61F) to 22C (72F)
• ADT important for plant development
• • leaves will unfold at the highest rate around 75F ADT
  • Around 80F ADT, development will slow but plants will stretch
  • 68 – 73F ADT is a good target
  • Especially important after initiation

• Two measurements of light:
• • intensity… FC or Lux
  • Quantity… moles/day
• Light intensity
• • 3,000 to 5,000 FC ideal

• need to plan for humidity control
• Disease pressure and reduced transpiration are both factors to consider with high humidity

• huge factor in making specs and finished quality
• • make it a priority
  • too late = stretched and weak plants
  • too early can result in sideways shoots and more stem breakage at shipping
  • best to space as canopy starts to close