Fungicide use for homeowners
Last week I started the discussion about pesticide use in the lawn and garden for homeowners, so I thought I might continue that discussion in regard to fungicides.
Like I previously mentioned, fungicides are used to kill or control fungal disease in plants. Not bacteria, not viral, and certainly not insect pests.
There is probably a fungal disease of which most home gardeners are closely acquainted with – powdery mildew. It strikes in the middle of summer when it is warm and humid. Not necessarily rainy, but when relative humidity is near 90% (Colorado State).
More: Pesticide use in the lawn and garden
There are many different powdery mildews that infect different plants because they have different preferred hosts. For example, the powdery mildew that attacks my cucumber and other cucurbit plants is not going to be the same powdery mildew strain that affects my zinnias, even though they present identically. The tell-tale talcum-like residue on the plant’s surface is indication of disease. The fruiting structure is about the size of a pinhead and will eventually turn black. These structures are how the disease can overwinter in a garden.
Because this fungal disease is so prevalent, how can you control it?
Well, the first option would be to plant powdery mildew resistant varieties. However, since this is an article on fungicides, let’s talk chemical control. As with insecticides, you want to make sure that the fungicide you select is suitable for use on the plant that is infected and the fungicide is labeled for control of powdery mildew. When selecting a fungicide for powdery mildew, look for the one of the below active ingredients: Myclobutanil, Sulfur, Propiconazole, Thiophanate-methyl, Chlorothalonil, Horticultural oil, Neem oil extract, Copper, Tebuconazole, Potassium bicarbonate and Bacillus subtilis.
Now remember, the label is the law. For most vegetable crops, you can look for a fungicide that is sulfur or copper based or has chlorothalonil, horticultural oil, or potassium bicarbonate (Clemson University) as a way to narrow down the search. If plants have already been infected with powdery mildew, unfortunately there is no curing the disease, but instead controlling disease. Spraying fungicide on affected plants can prevent the infection from worsening, and spraying fungicides as a preventative on neighboring plants of the same variety can help them from achieving the same fate.
A relative of powdery mildew in cucurbits is downy mildew, a much more severe fungal disease. There are sentinel plots across the country to keep watch for when and where the disease is moving to inform growers’ fungicide applications. The unfortunate bit about downy mildew is that when the plant finally starts showing signs, it is too late to save it and plants will likely be lost. That is when preventative fungicide applications can be useful.
Fungicides and other pesticides can certainly come in handy when cultural methods are cutting it anymore. Remember, the label is the law, and if you need more help – give us a call!
Upcoming events
Join us for a Poultry Biosecurity Webinar on May 31 at 6:30 p.m. Whether you raise poultry in your backyard, as a hobby, or as a 4-H project, biosecurity should be one of your top priorities. In light of recent cases of HPAI, or Highly Pathogenic Avian Influenza, it is important to have a plan in place should any flock health issues arise. This webinar will discuss biosecurity and health management practices for backyard flocks and 4-H poultry projects, and how to apply those practices to some of the more common poultry diseases. Please register at go.osu.edu/poultrybio22.
A Forages for Horses Pasture Walk will be held on Tuesday, June 7 from 6 to 8 p.m. at the ATI Equine Facility. Topics will include fescue toxicosis and poisonous weeds, rotational grazing, and pasture evaluation. Dinner will be provided. Registration is requested for preparation of materials and catering. Cost to attend is $15 if registered by June 1 and $20 if registered between June 1 and June 6. Please call 330-264-8722 to register.
This article originally appeared on The Daily Record: Are fungicides right for your garden?
