3/20/2024 - By Dr. Aaron Palmateer

Managing pests and disease in flowering plants is no trivial matter and can be particularly challenging in the spring when environmental conditions become highly favorable for outbreaks. This is especially true for bedding plants which have succumbed to some of the most devastating pests and diseases (i.e., rusts, mildews and insect transmitted viruses). Depending on the species, they are susceptible to the most challenging pests/diseases to control, such as thrips and Botrytis.

Bedding plants start from seed or cuttings and throughout the production process are often moved from one greenhouse operation to another. This increases the risk of introducing and spreading pests and diseases. With the diversity of bedding plant species and varieties currently available, many greenhouse operations are growing numerous types of plants, which makes it even more difficult to stay informed of all the potential problems. Growers are challenged to develop efficient production plans that incorporate as many tactics as possible to maximize plant health and minimize opportunities for pest and disease outbreaks.

Why Bedding Plant Management Programs are Important

The most successful pest and disease management programs are those that start clean and remain clean. Sanitation and exclusion are two of the most important components of integrated pest management (IPM) and when practiced can be very cost-effective.

·         Quick removal of plant material that is infected or infested reduces pest and pathogen populations.

·         Disinfecting the area along with tools and equipment that have been in contact and creating physical barriers (i.e., screens).

·         And implementing plant monitoring and scouting guidelines will minimize pests and disease outbreaks.

·         It is especially important to inspect all new plant material and not to accept plants that appear unhealthy or that may be infested with pests.

One main objective is to minimize the introduction of pests and pathogens and make the environment unfavorable for pests and disease outbreaks, which includes optimizing growing conditions to prevent plant stress. Optimizing these conditions means providing adequate nutrition and favorable temperature, moisture, and lighting in production. You can prevent costly disease outbreaks by closely monitoring irrigation practices to minimize over-watering and reduce leaf wetness duration. The use of sticky cards for early pest detection, and identification, to monitor population levels, and to aid in timing for pest control measures, contributes to more sustainable and cost-effective pest control.

Plant Management for Commercial Nursery Greenhouses

Even after implementing an integrated approach with these practices, commercial greenhouse and nursery production most often contain high plant populations consisting of thousands to sometimes millions of one plant species being produced under the same conditions, increasing their vulnerability to pests and diseases. Plus, when outbreaks occur, their uniformity allows for rapid spread. Unless there is host-plant resistance, these conditions justify the need for pesticides and make preventative applications essential to effectively control plant pests and diseases.

Once an accurate identification and diagnosis is obtained, growers should make informed decisions by relying on past management records. For newly introduced pests and pathogens, rely on the expertise of others. These people can be university extension specialists or private consultants, and you can always reach out to your local Harrell’s Representative for further assistance. Knowing the causal agent allows growers to make an informed management decision, which often saves time and money, and reduces the stress and frustration that comes along with losing plants.

Reach Out to Your Local Harrell’s Rep for More on Plant Management

Being proactive and making informed pest and disease management decisions are more likely to lead to positive outcomes that ensure resources such as time, money and labor, are allocated wisely and used optimally. Reach out to your local Harrell's rep to learn more and curate your management program.