Root Aphid Misconceptions

Many growers turn to biological control agents (BCAs) to effectively control foliar aphids; why should root aphids be any different? The difference lies in location, location, location! Root aphids tend to infest the entire container profile. Wherever plant roots are found, root aphids will follow. Root aphids hide out in any available crevice, providing a seemingly endless source of re-infestation. These deep colonies are the sticking point for most BCAs. Nevertheless, many growers have heard rumors of success with various BCAs. This tech tip will examine a few such BCA/root aphid relationships.

Stratiolaelaps scimitus (Hypoaspis) mites 

Hypoaspis miles, also known as Stratiolaelaps scimitus, is a soil-dwelling predatory mite with the ability to survive for long periods of time in the crop media. Their primary prey consists of fungus gnats, shore flies, and thrips pupae. This BCA reproduces in high numbers, quickly establishing populations. Hypoaspis mites have been observed feeding on root aphids, but their limiting factor is physical access. Hypoaspis mites are only active in the top and bottom inch of container media. Deeper aphid colonies will remain untouched, providing new waves of pests as these colonies continue to feed on plant roots and reproduce. 

Nematodes 

Nematodes for use as biological controls have been established as an easy and effective tool for growers to use. From fungus gnats and shore flies to thrips pupae, their efficacy is well understood. Nematodes have the advantage of being able to be drenched into media, though typical nematode applications only target the top two inches of soil. Nematologists confirm that certain species of beneficial nematodes, specifically Heterorhabditis bacteriophora, have the capability to harass and infect root aphids, but their capacity to kill is far outpaced by the root aphids’ speed of reproduction. 

Dalotia/Atheta/Rove beetle 

Rove beetles are media-dwelling insects that help growers manage shore flies, fungus gnats, thrips pupae, springtails, and other soil-dwelling pests. They are aggressive feeders, spending most of their time at media-level but adults may fly around at night in search of prey. Being a generalist predator, they may indeed prey upon root aphids that they encounter, but their contact is limited. Dalotia beetles dwell primarily in the top ½ inch of soil or media, again leaving deeper hidden colonies of aphids untouched. 

So, what DOES work?

Our current recommendations fall back on full-pot-volume drenches of biopesticides and insect growth regulators. Specifically, the combination of B. bassiana fungal spores with an azadirachtin product has shown some level of control in production environments. Drenches target root aphids while sprays control foliar aphids and fliers. A tank mix and weekly spray/drench of these products can go a long way toward achieving or maintaining control of both root and foliar aphid species. For more information contact your local Griffin rep or the GGSPro team.

Product Name		Item Number
BotaniGard WP		70-12521
BotaniGard ES		70-12511
BioCeres		70-1245
Velifer		70-9540
AzaGuard		70-1225
Azatin O		70-12301
Molt-X		70-2410
Aza-Direct		70-1222

Printable version

pH Correction for Irrigation Water

 Why? When? How?

Most growers know that correcting pH is important, but they don't always know why. When we correct the pH in irrigation water, we are actually adjusting the irrigation water alkalinity, but why are we doing that?

Figure 1

To understand, we need to define pH. In simple terms, the pH of a solution relates to the concentration of hydrogen cations (H+). The pH scale goes from 1 to 14, where the lower the pH (high H+ concentration), the more acidic; the higher the pH (low concentration of H+), the more basic.  

Why is irrigation water pH important in CEA? The nutrient availability for plants is affected by pH (Fig 1). Whereas Iron (Fe), Manganese (Mn), Boron (B), Zinc (Zn), and Copper (Cu) are more available at low pH values, Calcium (Ca) and Magnesium (Mg) are more available at higher pH values. At very low pH, however, the increase in Fe, Mn, and Al (Aluminum) can become toxic. Therefore, between 5.5 and 6.2, most micronutrients are available at proper levels.

Why do we correct irrigation water alkalinity? The concept “alkalinity,” is a measure of the resistance of a water solution to change its pH. When acid is added to the irrigation water, the H+ of the acid first react with the carbonates and bicarbonates on the water forming CO2 and water. Initially, pH decreases slowly. When no more alkalinity is left, the pH will drop abruptly. 

We measure alkalinity in ppm.  Even though it’s closely related to pH, two different water samples could have similar pH values but different levels of alkalinity. It’s going to take much more acid to lower the water sample's pH with more alkalinity than the one with less. 

Carbonates and bicarbonates brought by the irrigation water will react with H+ in the growing media and increase its pH, lowering the micronutrient availability.  Plants will suffer micronutrient deficiencies. But completely removing the alkalinity is not necessarily good. Most fertilizers are acidifying in nature; if our irrigation water does not have any alkalinity, the acidifying fertilizer can lower the growing media pH to toxic levels. This case can be observed with RO water, where all alkalinity was removed, and potassium bicarbonate is needed to increase the alkalinity to a desirable value of 60-70 ppm.

We correct pH (mostly lower it) to correct alkalinity and optimize micronutrient availability. In some cases, we start with water that has no alkalinity. Then we need to adjust the pH up due to the natural acidifying quality of most fertilizer formulas.

Figure 2

Our injectors correct pH by proportionally injecting acidsor bases for your fertilizer formula blend (Figure 2). How much? And how? Let the GGSPro andDilution Solutions team help; give us a call!


Jose Rodriguez
Agronomist – PhD Engineering Sciences
Business Development Manager
Dosatron / Dilution Solutions
jose.rodriguez@dosatronusa.com
863-258-6888

Product Name		Item Number
Dosatron 14 GPM Injector with Bypass		33-2417
Dosatron Etatron eOne Kit Low MicroDoser Kit		218-1820
Dosatron Etatron eOne Kit HI MicroDoser Kit		218-1821
Dosatron Etatron Ultrasonic Lo MicroDoser Cabinet		218-1822
Dosatron Etatron Ultrasonic Hi MicroDoser Cabinet		218-1829
Dosatron D132 Mega-Flo Injector		33-2428
Dosatron D400 Mega-Flo Injector		33-2429
Sulfuric Acid 93% Tech Grade 1GAL		75-5030
Sulfuric Acid 93% Tech Grade 15GAL		75-5034
Phosphoric Acid 75% Tech Grade 4-1GAL/CS		57-100239
JACKS CITRIC ACID 25 LB		J74321
JACKS POTASSIUM BICARBONATE 1 LB		91-2190
JACKS POTASSIUM BICARBONATE 25 LB		91-2191
General Hydroponics pH Up 1 gal		HGC722095
General Hydroponics pH Down 1 gal		HGC722125
Dosatron Meter pH/Temp Hydro		33-2710
Dosatron Meter pH/Temp Pro		33-2715
Dosatron Replacement Sensor pH		33-2725
Dosatron Storage Solution pH Electrode 600		33-2740

Printable version

Controlling Pest Caterpillar in The Field

Trichogramma wasp parasitizing lepidoptera egg.

Lepidoptera species are one of the top pests of hemp and cannabis production and may appear anytime from early spring well into fall.

Types of Lepidoptera

Species such as Eurasian Hemp Borer, European Corn Borer, Corn Earworm, and many others cause significant damage when left unchecked.

Types of Damage

Damage from these pests commonly takes two forms: stem boring or leaf chewing. Stem boring refers to when the insect eats its way into the plant, while leaf chewing refers to defoliation.

Understanding and controlling the lifecycles of these pests is key to season-long damage protection. Lepidoptera typically go through four main stages: egg, larval, pupal, and adult stage. The larval stage is represented by caterpillars. The pupal is the cocoon stage when they are often dormant. The adult stages appear as moths, flies, or butterflies. Different control strategies target different life stages, so timing control activities is very important.

Cultural management can help growers handle the larval and adult life-stages and generally follows these two focuses.  

·       Environmental Cleanup - Through the vigilant season-long reduction of weeds and plant debris, growers remove the preferred habitat, potential food sources, or breeding areas. This is effective at combating all four stages

·       Traps - The use of UV light traps and pheromone lures helps manage the population of adult moths when properly positioned and employed.

Spray treatments can be added to cultural control strategies and are highly effective for the larval stage, however they may not be approved for all locations or all crops.

Biological Control Agent (BCA) Options

Various species of Trichogramma wasps target the egg stage of many Lepidoptera. These biological control agents (BCAs) can be released either in a loose bulk carrier throughout the crop or as eggs on cards that can be hung on plants. As the Trichogramma eggs hatch, the wasps emerge and hunt down Lepidoptera eggs to parasitize. Once eggs have been attacked by wasps, the pest life cycle halts. Weekly applications should begin in early June to catch the first generation of eggs and continue throughout production through August. 

Different species of Trichogramma prey on different Lepidoptera species. Contact your GGSPro BCA specialist for help determining which species is most appropriate for your operation.

Griffin Lepidoptera Control Products

Product Name	Supplier	Species	Size	Item Number
Tricholine	Bioline	T. Brassicae	20K or 10K pupae	SB0451-04, SB0451-01
TRICHOforce B	Beneficial Insectary	T. Brassicae	10K pupae	30TBH
Trichogramma	Beneficial Insectary	Mixed	100k pupae	30TBH

Printable version

Surface Sanitation with SaniDate 5.0

-BioSafe Technical Team

Facility infestations can quickly go from bad to worse in the absence of proper sanitation practices. Cross contamination from host sites can affect crop health and reduce yields.
A thorough sanitation program significantly impedes the spread of bacteria and disease by removing favorable conditions for their development and addressing critical control points.

 

Critical control points are potential areas of infection (and re-infection) within growing and
non-crop areas such as under benches, entryways and cooling pads. Identifying these points is be integral for developing your facility’s program. Keep in mind sanitation is not just an ‘end of the season’ activity, it should be practiced throughout the production cycle. Standardizing practices such as spraying/foaming racks, empty benches, walkways and sanitizing containers, trays and equipment will maintain a clean environment.

 

Hard surfaces with algae and organic matter create a favorable environment pathogens and pests thrive in, including fungus gnats and shore flies. These pests can transmit contamination and infection throughout the crop. A general cleaning step is ideal to remove organic and mineral deposits, allowing sanitizer to have better contact on the targeted area and improving efficacy. Once areas have been cleaned, utilizing a sanitizer with no-rinse step, like SaniDate® 5.0, will ensure optimal productivity.

 

SaniDate 5.0 kills pathogens on contact, does not require a post-rinse and leaves no harmful residue. Its versatility of applications and use sites make it the ideal sanitation/disinfection tool to address many, if not all, critical control points in your facility.

 

Sanitation may be a chore, but it is important for preventing many unforeseen incidents which can deprive crops of optimal health. Choose the best methods and tools that work for your facility, but always remember – an ounce of prevention is worth a pound of cure.

SaniDate 5.0 Product Offerings

Griffin Product #	Description
71-35001	2.5 Gal 28.3%, OMRI
71-35001-CA	2.5 Gal 28.3%. OMRI, CA Label
71-35101	5 Gal 28.3%, OMRI
71-35151	30 Gal 28.3%, OMRI
71-35151-CA	30 Gal 28.3%, OMRI, CA Label

Preventing Damping Off in Microgreens Production

71-3040 Triathlon BA 98.85% 1GAL
OMRI OHP EPA# 70051-107-59807

The production of microgreens is increasing in popularity across the country.  It can be done on a small scale or large scale, lending itself to the Grown Local Production Theme.

Growers typically sow in a high density into a 1-inch propagation tray with media, either loose fill or a mat. Once sub-irrigated to water in, the flats are covered or held under dark conditions for 3 – 5 days for germination.  After the germination period, the flats are uncovered and exposed to light to support healthy growth.  Harvest occurs 10 – 14 days later, depending on the species.

One of the major issues for microgreens production is the presence of damping off, usually caused by Botrytis or Rhizoctonia, which can be encouraged due to the planting density and growing conditions. Working with Farm Boy Micros, OHP developed a strategy to combat damping off with the application of Triathlon BA.

Triathlon BA is OMRI listed and exempt from tolerances, making it ideal for use in microgreens production. The protocol is simple. After sowing, spray the seeds with Triathlon BA at a rate of 1.28 oz/gal, or 1 gal/100 gal. This treatment protects the seeds and seedlings as they germinate, with dramatic results. The pictures below show the difference between treated (L) and untreated (R). 

Tipburn in Hydroponic Lettuce

By: Dan Gillespie, Technical Specialist

Tipburn is among the most common issues experienced in controlled environment lettuce production. Tipburn occurs as browning of the edges or tips of new young leaves (Figure 1).

Figure 1. Tipburn on young lettuce leaves

Tipburn in lettuce is most often caused by calcium deficiency. However, this deficiencyis usually not a result of insufficient calcium in the nutrient solution. To understand why tip burn occurs (and how to avoid it), we need to understand how calcium travels through the plant

Calcium moves through the plant differently than nearly all other nutrients: It requires mass flow of water. Think of it as a hose that must be turned on for the calcium to move into the plant. Mass flow is driven by transpiration, so high transpiration rates will enhance calcium uptake and translocation, whereas, low transpiration rates will decrease calcium uptake and translocation. When a head of lettuce grows, the growing point becomes enclosed by older mature leaves, creating a high humidity microclimate. This microclimate results in decreased transpiration, which leads to the tip burn.  

The first step in preventing tipburn is ensuring that calcium is not lacking in the nutrient solution and that your fertilizer formula has a proper ratio of potassium, calcium, and magnesium. Source water with calcium concentration above 40 ppm is typically a good candidate for one-part fertilizer systems such as Jack’s Nutrients 12-4-16 RO or Jack’s Nutrients 15-5-20 Tap. However, source water with lower concentrations of calcium will typically require the use of a two-part fertilizer system, such as Jack’s Nutrients Part A 12-4-26 and Cal Nit Part B 15-0-0. Additionally, nutrient solution electrical conductivity should generally not exceed 2.5 mS/cm, as high soluble salt levels will decrease water and calcium uptake. Note that all Jack’s Nutrients provide the proper balance of nutrients.

As stated above, even when calcium levels in the nutrient solution are adequate, tipburn may still occur.  Improve airflow around the growing tip with the use of vertical airflow fans.Vertical airflow should provide just enough air movement to gently move plant leaves (0.3-0.5 m/sec). This will eliminate the microclimate and facilitate calcium uptake.

If vertical airflow fans cannot be installed, another option to prevent tipburn is increasing night time humidity above 95%. High nighttime humidity leads to increased root pressure, and thus, increases water and calcium translocation to the growing point of the plant. However, this strategy can increase the threat of fungal diseases that thrive in high humidity environments. 

Product Name		Item Number
Jack's Nutirents 12-4-16 RO		33-12416
Jack's Nutirents 15-5-20 Tap		33-15520
Jack's Nutirents 5-12-26 FeED Part A		33-51226
Jack's Nutirents 15-0-0 Boost Cal Nit Part B		33-79080

Using Sticky Cards for Insect Monitoring

By: GGSPro Technical Specialists

Sticky cards are the best monitoring tool available for flying insects, such as thrips, fungus gnat
adults, shorefly adults, whiteflies and winged aphids. Using cards for active monitoring of these pests supports proactive decision making for best management of pest populations.

Sticky cards are available in solid yellow, solid blue, and bi-colored forms (two-sided, yellow on one side and blue on the other). Some sticky cards are pre-printed with a grid pattern that allows for quicker counting. Sticky cards come with a protective sheet that is removed to expose the sticky surface. To make these easier to work with, take a tip from the pros and keep your sticky cards refrigerated until use.

Proper use of the cards will generate the best data. Prior to placing cards in the crop, date and number each card with a consistent location code. Sticky cards should be placed above the crop with one third of the card in the canopy. Additionally, place some cards vertically just above the crop canopy; avoid placing sticky cards too high above foliage to ensure you pick up all flying insects. To monitor for insects emerging from the media (e.g. thrips and fungus gnats), place yellow sticky cards horizontally just above the media surface. Growers generally use 1-2 cards per 1000 square feet, increasing to 3-4 cards per 1000 square feet when monitoring for thrips or when monitoring higher value crops. Remember to place additional sticky cards near doors, vents or areas of concern.

Perform weekly counts of pests and beneficials captured on the cards, using a 16x hand lens to identify the insects. When recorded, this data can be analyzed for population trends on which management decisions can be made. Be sure to note any specific weather patterns in your records, too. Cards are generally replaced weekly. However, when pest activity is low, cards may be used for several weeks. If used over multiple weeks, take another tip from the pros: Use different colored Sharpies to circle and count the pests each week so you are sure to only count the new pests in later weeks.

Speaking of beneficials, when releasing Aphidius, Encarsia, Eretmocerus or Orius, take cards down on the day of release to minimize capture of the good bugs. Return the cards to the crop a few days after release.

Product		Item Number
2-color blue/yellow sticky cards, 4"x5"; 10 per pack		74-3668
Yellow moisture resistant monitoring cards, 3"x5"; 50 per pack		74-36705
Trapline T Yellow Roller trap 6"x328'		SB8051-05
Sticky yellow trap roll 12"x300'		74-12300
Sticky yellow trap roll 6"x1500'		74-61500
Sticky blue trap roll 6"x1500'		74-61500B

Controlling Water Flow

Written by:  Kurt Becker, Dramm Corporation 

You may have heard that the most important person on a cultivation team is the person with the hose in their hand. Proper irrigation can make or break a crop. One challenge is to ensure that proper flow and pressure to address different needs. This is complicated by the fact that crop needs change dramatically over a short period of time. How do you help your team meet these changing needs? You give them the right watering tools! 

Dramm produces a full assortment of professional watering tools, including water breakers. These specialized nozzles break the water into smaller droplets and streams, simulating rain, which softens impact on plants and media while absorbing and providing needed oxygen to the roots. Different water breakers tailor the delivery pattern, flow and volume for specific containers, media and plant stages. In addition to the essential, high-flow 400 series, Dramm manufactures innovative, specialized water breakers to meet all irrigation needs. 

The 1000PL Series. 

Starting with the original Redhead, the 1000PL uses 1000 smaller holes in a stainless steel disk. This allows for a softer pattern for younger plants along with the ability to throttle the flow while still keeping a pattern. Now, the 1000PLs are available in Narrow, Medium and Wide versions offering different amounts of water per square inch of coverage. 

750PL 

The 750PL reduces the flow even further. Using the same size hole as the 1000PL, but using fewer holes, the 750PL applies less water. This allows for lighter watering when required. The 750PL throws a wide pattern for less water per square inch of coverage.

Fan Nozzle 

Most fan nozzles are consumer tools and have uneven patterns. Dramm’s Commercial Fan Nozzle was developed to offer a precise, rectangular pattern that allows for medium to very low flow while still producing even streams. 

350PL Screen-Aire 

The 350 lands at the opposite end of the spectrum, delivering a very high flow rate with a soft, aerated pattern. Water exits the nozzle like a kitchen faucet, a single stream full of air bubbles. This allows for a lot of water without disturbing soil or top-dressed fertilizers. Great for quick watering of containers. The 350 is also perfect for rewetting dry media, as the bubbles hold the water on the surface of the media longer. 

Valves 

Remember to match the valve to the nozzle to allow precise control of flow rate. Valve operation is important to note. Does the watering require on-off operation or is it turn on and go? The OneTouch and OneTouch HighFlow offer easy control of the flow. Other valves, like the 300 Brass Shut-Off are high flow, quarter turn valves for quick watering.

	Description	Item Number
	Dramm 400AL 400 Water Breaker (alum, full)	80170002
	Dramm 400PL Water Breaker (blue, full, w/ring)	33-6101
	Dramm 170 PL Plastic water breaker	41-600101
	Dramm 350PL ScreenAire Water Breaker	33-350PLC
	Dramm 750PL Lemonhead Water Breaker (low)	33-5234
	Dramm 1000PL RedHead Water Breaker (medium)	33-5233
	Dramm 1000PL Orange Water Breaker (wide)	33-5237
	Dramm 1000PL Green Water Breaker (narrow)	33-5236
	Dramm 79001 Commercial Fan Nozzle	33-2079
	Dramm 510 brass seedling nozzle	33-5235
	Dramm Fogg-It nozzle fine 610 F	33-610F
	Dramm 610SF 1/2gpm Fogg-It Hose Nozzle (SF)	33-5327
	Dramm #300C Brass Shut Off Valve Heavy Duty	41-400300
	Dramm 74C Wide Body Shut Off Valve, Plastic	33-51051
	Dramm QAV Shut Off Valve	44-5607
	Dramm One Touch Valve Handle, Low Flow	33-14700
	Dramm OneTouch Valve Handle, High Flow	33-5365