Photo courtesy of Syngenta

In late spring and early summer, growers need to mind their mildews. Greenhouse Management recently spoke with Nancy Rechcigl, technical services manager at Syngenta, about these diseases and the role fungicides play in controlling them.

Greenhouse Management: May and June can be difficult months for mildews. What is the difference between powdery and downy mildew?

Nancy Rechcigl: Downy and powdery mildew pathogens are both obligate parasites but differ in their symptoms and fungal classification. Downy mildews are Oomycetes while powdery mildews are Ascomycetes. This distinction is important when selecting fungicides for control.

Powdery mildews form white colonies on the surface of leaves, stems and flowers. They will likely appear in the spring or early summer when temperatures are 62-72° F and the relative humidity is 70 percent or greater.

Plants infected by downy mildew will have blotchy, discolored areas on the leaves, often within the veins. Under the right environmental conditions, sporulation creates a fuzzy coating under the leaves below the discolored areas. Systemic infections can also cause distortion of emerging leaves and flower buds, defoliation and stunted plants.

Temperatures from 50-72° F are favorable for most downy mildew fungi, but some can grow in higher temperatures such as those infecting roses (up to 82° F) and salvia (up to 90° F). All downy mildews require relative humidity greater than 85 percent for six-plus hours when the leaves are wet.

GM: How should these diseases be controlled?

NR: When the environmental conditions are conducive to disease development, powdery mildews should be controlled by alternating fungicides from FRAC Groups M, 3, 7+11, 9+12. Horticultural oils and some microbials can also provide suppression. Downy mildews should be controlled by alternating fungicides from FRAC Groups M, 4, 21, 40, 43, 45, U-49. Fungicides in FRAC Group 7+11 can protect against downy mildew as well as other diseases. Preventative applications are generally less expensive than curative, and result in higher plant quality.

GM: Why is product rotation so important to preventing mildews?

NR: Fungicide resistance can occur quicker in pathogens producing a lot of spores. Downy mildews are known to develop resistance very easily when exposed to a single active ingredient over time. To avoid resistance, you must rotate at least two to three products with different modes of action for each target problem. Programs should include a combination of products with systemic activity and contact or translaminar activity. A well-structured program will maximize each product’s strengths and leverage modes of action when they are most beneficial.

GM: What solutions does Syngenta offer that fit into a well-rounded fungicide program?

NR: Our downy mildew program includes the following fungicides: Subdue Maxx® (4) early in production, rotating to Mural® (7+11), Micora® (40) and Segovis® (U49). Our powdery mildew program includes the following fungicides: Daconil Ultrex® or Daconil Weatherstik® (M5) early in production, rotating to Palladium® (9+12), then Mural (7+11). In outdoor production rotations, include Concert® II (M+3) for powdery mildew.

GM: What resources does Syngenta have to help growers stop these diseases?

NR: Syngenta offers free, downloadable programs to help control powdery and downy mildew, as well as other common diseases at GreenCastOnline.com/Solutions

All photos are either the property of Syngenta or are used with permission.

©2019 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties. Please check with your local Extension Service to ensure registration status. Concert®, Daconil Ultrex®, Daconil Weatherstik®, GreenCast^®, Micora^®, Mural^®, Palladium^®, Segovis^® and Subdue Maxx^® are trademarks of a Syngenta Group Company. Syngenta Customer Center: 1-866-SYNGENT(A) (796-4368).

Photo courtesy of Argus Controls

Picking the right environmental control system, and understanding how it will affect plant growth, is a vital decision for any grower. Below, Argus Controls Vice President and General Manager E. Michael Heaven offers his advice for picking a system, how environmental control technology has improved and more.

Greenhouse Management: What are some tips for growers to pick the right environmental control system?

E. Michael Heaven: To select the right environmental control system, growers should ensure the control system can maintain the plants at the right temperature and relative humidity at the plant canopy regardless of environmental disturbances or intentionally introduced changes to fertigation, CO2 content, etc. If the environmental controls do not anticipate a feeding/watering cycle and ramp up dehumidification in advance, the plants will be unnecessarily stressed by wide swings in the environment. Growers should ask for performance guarantees at the plant canopy.

GM: Why is good service a key when selecting an environmental control system?

EMH: If you have a crop-threatening emergency, you need to know you can reach someone 24/7 that knows your environmental controls and can support you through the emergency. You do not want to reach a building management technician that has never seen an environment with plants in it and must learn your system from scratch.

GM: How has environmental control technology improved over the last few years?

EMH: There are more plant-specific algorithms that use measurements of inputs, outputs and sensor readings to maintain your plants on the right vapor pressure deficit trajectory for optimal, stress-free growth, that model and control the plant transpiration rate and that control the ever expanding world of variable intensity and spectrum lighting. Machine-learning applications are being developed for yield optimization while balancing the economic factors including energy, labor, materials, etc. New visual tools are available on their mobile devices to see the performance of a grow operation at a glance and manipulate targets from wherever they are.

GM: What are some common mistakes growers make with their environmental control systems?

EMH: Some of the common mistakes are 1) implementing building management systems designed for people, not plants 2) designing the heating/cooling/dehumidification system for a large greenhouse/grow room without considering the impact of the plants response to various inputs 3) designing a system without an experienced grower at the design table 4) failure to use lower energy elements to control the environment (such as vents, shades, fans, light diming) before switching on more expensive cooling/heating systems 5) inadequate range of inputs to control the environment as plants grow or more plants are added (such as CO2 injection at certain light levels) 6) implementing on/off HVAC controls, instead of proportional controls, which result in environments oscillating after every disturbance 7) not using enough sensors at adequate resolution and update frequency to implement zone control throughout a large growing environment so disturbances are localized to only one zone.

Photo courtesy of Svensson

Climate screens can be useful tools for growers not just in efforts to save energy, but in improving crop quality. Below, Mauricio Manotas, President of Svensson's Americas Subsidiary, discusses the benefits of a climate screen, who they work with on other technology and more.

Greenhouse Management: What are the benefits of using a climate screen?

Mauricio Manotas: Climate screens were developed in the early 70s mainly as a source to save energy, but over time, growers have found many other uses and [climate screens] have become a key tool to grow a better crop. Now, growers have the ability to control control energy consumption, light levels, humidity and temperature, which are the main elements needed for plant photosynthesis.

GM: What are some of the climate screen options available to growers?

MM: These days we have enough options to accommodate pretty much any situation. From climate screens used in areas with low light levels and cold temperatures to shade screens used in hot climates with excess of radiation and high humidity levels. Also, products that diffuse light and control day length (blackout) and meet the fire code requirements in every country.

GM: How can a grower pick the right climate screen for their business?

MM: We encourage every grower to reach out to their screen supplier or greenhouse builder and request personalized climate advice. There is not really an “off-the-shelf” product that is going to work for every crop and location. Here at Svensson, before recommending any options, we communicate with the grower to make sure we understand their business, cycles, location, crop, greenhouse type and additional equipment. With that information we create a personalized solution that fits that specific case.

GM: Do climate screens work well when used with other tools growers use (lighting, cooling systems, etc.) to control their environments?

MM: A greenhouse is a microcosm where all the equipment needs to work well together. Otherwise, we end up having more problems than benefits. The “brains” of all this is the climate computer system where you can control every piece of equipment that goes into the greenhouse, from irrigation to lights and screens. They all are programed when setting up the parameters to work in sync. This is very important in any greenhouse operation.

GM: What can Svensson do to help growers pick the right climate screens for their greenhouses?

MM: Here at Svensson we have a consultancy team that visits growers, and based on their request, they create a document that is called SCA (Svensson Climate Advice). This document takes into consideration all aspects of the growing operation and is given to the grower so he can use it as baseline. We also follow up during the growing season, making sure our products are meeting the expectations and sometimes collaborate with other components manufacturers (climate control computers, etc.) to make sure the grower makes the most of his or her investment. We have always looked at the growers as our partners in business and our success is fully tied with their success.

Greenhouse Management: What does EBS do?

Mike Koucky: We are a technology company that solves the critical need for electronic applicant tracking, onboarding, I-9 with E-Verify, Work Opportunity Tax Credit (WOTC) and completing the entire Affordable Care Act (ACA) Chain of Custody Metrics and Notification Compliance.

We also offer a Minimal Essential Coverage (MEC) and fixed-indemnity plan, which protects employers from schedule A fines and penalties, and allows them to offer insurance to all employees, part-time or full-time.

GM: What do you mean when you say, “electronic on-boarding process?”

MK: We digitize the entire new hire packet that an organization uses, such as company policies/procedures, I-9, W-4 and WOTC forms, as well as the ACA Chain of Custody. In other words, we are taking paperwork and digitizing it, which in turn drastically reduces the amount of time it takes the employee, back office and employer to complete these forms.

GM: How can EBS help greenhouses find employees in this tough market?

MK: We instantly post to more than 22 national job boards and local listings that are available in your community, as well as Craigslist and social media to attract employees. The entire system is mobile-friendly. With MEC and Fixed-Indemnity, employers are able to promote that they offer insurance to ALL employees. Having an affordable insurance plan to offer your staff is also proven to help with retention.

GM: How do you help companies navigate the ACA and how much of a risk is the ACA?

MK: We protect companies from the IRS by managing the entire ACA chain of custody process. Starting by showing proof at hire that the company offered insurance, tracking, calculating, and notifying employees if they become eligible for coverage. This allows the employee to either accept or decline coverage. Employers can then show proof to the IRS that the employee was offered coverage.

Completion of ACA forms 1094c and 1095c are then filed directly to the IRS, so [businesses] don’t have to. Our technology does all the work, so people don’t have to, and we eliminate human error.

Robert Lemon: HR managers do not have to take the blame for ACA fines and penalties. The risk of the ACA is terminal to any business. The fines and penalties will put you out of business for non-compliance. I can’t stress that enough. Fines and penalties are not just punitive, they are terminal.

Our technology manages this entire process, ensuring that our clients do not experience any fines and penalties. If, in fact, one of our clients receives a 226J [penalty form] from the IRS, we will work with the IRS directly to provide proof of everything, advocating for the fines and penalties to be removed.

At the end of the day, why allow the human element, that can make mistakes, and cause the company to go out of business, when you have technology that can do it for you and cost less?

GM: How much is this going to cost greenhouse growers?

RL: In short, absolutely nothing. In fact, we pay for ourselves through the unknown, what we call hidden asset or organic profitability that most organizations don’t know that they have — the Work Opportunity Tax Credit.

According to the Department of Labor, 20% of all new hires qualify for WOTC. Our average credit value runs around $1,000 per employee and can go as high as $2,400, depending on how long they work for you.