Groff's Plant Farm Images

Bugs and Other Signs of the Season

Published: Tue May 23rd 2017

Last week a leaf poked me in the eye. I spend a few hours a week looking through the greenhouses scouting for insects, searching for foliar disease and identifying plants with exceptional flowers or foliage to feature on Facebook or Instagram. Nothing like multi-tasking.

I was looking for thrips when I was assaulted. Western Flower Thrips are very small insects with rasping mouth parts that do three harmful things:

1. Scrape the undersides of leaves causing bronzing.

2. Feed on pollen and other tender tissues in the buds. Often this causes distortion of the flower petals or leaves.

3. Serve as a vector for disease. Thrips and their sinister mouth parts cause wounding of the plant tissue and allow viruses like Tobacco Mosaic Virus, or Impatiens Necrotic Spot Virus entry into otherwise healthy tissues. This is probably the most harmful thing thrips do.

These virus weaken the plant, cause foliar discoloration and stunting.

Thrips are really small; about half the size of the tip of my pinkie nail. The best way to locate them is to blow on open flowers and lightly tap the flower onto a white piece of paper. The carbon dioxide in your breath will stun them momentarily and since they are a light orangish-brown color they show up well against white paper. They look like pollen that moves. It is a fun trick for kids. At least my kids think it’s interesting.

We know to look for thrips around the time the dogwood trees bloom. Phenology is the study of how the biological world times phenomena such as when trees bloom, frogs mate, birds migrate and insects pupate. These events are often based on light, temperature and precipitation. Being observant of what natural events coincide help you to expect one when you see the other.

Another example of two unrelated phenomenon occurring together are the shad fish running the streams and the service berry plants blooming. These two events have become so linked over the years that service berries are commonly called “shadbush”.

Ohio State University has a phenology network that has 36 identical gardens throughout the state that are monitored for bloom timing and insect activity. This data is used to create a “biological calendar” for the region. What an interesting concept. This information is also fed into a national database. According to their data, the spring of 2017 through the end of April was about 20 days early. The weather was most similar to the spring of 2012, unfortunately that was a hot dry summer. Hopefully, history will not repeat itself.

I poked myself in the eye, which gave me a good excuse to stay in the house for a day. I don’t think you could call that phenology, but it is a reliable fact that most greenhouse growers could use a nap the end of May.