Now that summer is in full swing, our gardens should be growing well now. It is at this time of the year when we always tend to see many different diseases and environmental conditions on our vegetable garden plants.
One of the most common problems we see early in the growing season is blossom end rot. This is an environmental condition where the end of the fruit that is not attached to the plant begins to rot away. It starts as a flat, dry, sunken brown rot on the blossom end of the fruits. Gray mold can occur in this rotten spot of the fruit, as it progresses. Blossom end rot is caused by a calcium deficiency while producing fruit. In Nebraska, there is rarely a lack of calcium in the soil, but calcium needs to be dissolved in water to be absorbed into the plant, so, it often occurs in conditions of dry soil. Blossom end rot can occur in tomatoes, peppers, cucumbers, zucchini, or watermelons.
Drought stress, low daytime humidity, high temperatures, and rapid vine growth favor blossom end rot. Applying calcium to the soil or to the plant is not beneficial. It is best to just maintain consistently moist but not saturated soil. It will also help to use organic mulch near the base of plants to keep the soils moist. Often the first ripe fruits are affected and later produce is fine. Remove infected fruits at the beginning of the season and later ripening fruits should not be affected.
Scorch is another problem we often see in the summer months, especially when the temperatures range as high as it has been recently and rain is scarce. Currently scorch has been found on bean plants. When scorch appears on our plants the edges of the leaves will turn brown and papery. Wilting and leaf scorch can be reduced with regular watering during prolonged dry periods. Mulching around the base of plants will hold moisture in the soil.
Squash bugs and squash vine borer are seen in our gardens every year. With squash bugs, we will see yellow speckling on the leaves and feeding damage can appear on the fruits. You may also see rusty colored eggs on the underside of the leaves that can be removed and destroyed. With Squash Vine Borer, rapid death and wilting of the plants will occur, once they are found in our plants, there is no cure.. These pests feed on plants in the cucurbit family, which includes zucchini, squash, cantaloupe, watermelon, cucumbers, pumpkins, gourds, etc. Squash vine borer can be controlled by wrapping the stem of your plants with aluminum foil or a toilet paper or paper towel tube to stop the females from laying their eggs on your plants. Other controls include Carbaryl (Sevin), Permethrin (Eight), or bifenthrin (Bifen), or Bt for the squash vine borer. This will need to be reapplied every 10-14 days throughout the growing season. It is best to switch between at least two of these products to avoid resistance from developing. Always follow the label recommended rates and follow the pre-harvest interval listed on the label when harvesting fruits and vegetables after using chemicals. Spray the undersides of the leaves and the base of the plant thoroughly. All sprays should be done later in the evening to avoid damage to bees and other pollinators.
The information for this article came from Nebraska Extension’s Hort Update. This is a monthly news column covering seasonal information for Nebraska’s green industry professionals. It is produced monthly throughout the year by Nebraska Extension Educators from across the state. You can subscribe to this newsletter by going to hortupdate.unl.edu and selecting “subscribe” from the top tabs. You can also get there from the Gage County Horticulture Page from gage.unl.edu