Tomatoes often have problems with cracking caused by pressure inside the fruit that is more than the skin can handle. Cracks are usually on the upper part of the fruit and can be concentric (in concentric circles around the stem) or radial (radiating from the stem).
We don’t know everything about cracking but here is what we do know. Tomatoes have a root system that is very dense and fibrous and is quite efficient in picking up water. Unfortunately, the root system can become unbalanced with the top of the plant.
Early in the season it may be small in relation to the top growth resulting in blossom-end rot during hot dry weather. Later it may be so efficient that it provides too much water when we get rain or irrigate heavily after a dry spell. This quick influx of water can cause the tomato fruit to crack. Therefore, even, consistent watering can help with cracking.
Mulching will also help because it moderates moisture levels in the soil. However, you can do everything right and still have problems with cracking in some years.
We have evaluated varieties for cracking during our tomato trials at K-State. It takes several years worth of data to get a good feel for crack-resistant varieties, but we have found some real differences. Some varieties crack under about any condition and others are much more resistant. The difference seems to be pliability of skin rather than thickness – the more pliable the skin the more resistance to cracking.
The old variety Jet Star has been the most crack resistant of any we have tested including the newer types. Unfortunately, Jet Star is an indeterminate variety that puts out rampant growth. Newer varieties with more controlled growth are often more attractive to gardeners. Mountain Spring, Mountain Pride, Mountain Fresh, Floralina and Sun Leaper are smaller-vined types that have shown good resistance to cracking.
Tomato fruit sunscald
Extreme heat and bright sunlight can sunscald tomato fruit, leaving a light yellow to white-sunken spot that resembles a blister. This most often happens to fruit that is exposed to full sun after losing foliage to disease or tomato hornworms. Remove damaged fruit to encourage more fruit set. Sunburned fruit are rarely usable.
Tomatoes with thick, tough skin
Hot weather can lead to tomatoes with a thicker, tougher skin than normal. However, variety also plays a role with some varieties being more likely to produce a thick skin than others. There isn’t anything that can be done about this, of course, but hope for lower temperatures.
Cicada killer wasps
These large (1-1/3- to 1-5/8-inch long) wasps fly slowly above the ground. Cicada killers have a black body with yellow marks across the thorax and abdomen. Wings are reddish-orange.
Page 2 of 3 - Although these wasps are huge, they usually ignore people. Males may act aggressively if they are threatened, but are unable to sting. Females can sting, but are so passive that they rarely do. Even if they do sting, the pain is less than that of smaller wasps such as the yellow jacket or paper wasp and is similar to the sting of a sweat bee.
The cicada killer is a solitary wasp rather than a social wasp like the yellow jacket. The female nests in burrows in the ground. These burrows are quarter-size in diameter and can go 6 inches straight down and another 6 inches horizontally. Adults normally live 60 to 75 days from mid-July to mid-September and feed on flower nectar and sap. The adult female seeks cicadas on the trunks and lower limbs of trees. She stings her prey, flips it over, straddles it and carries it to her burrow. If she has a tree to climb, she will fly with it. If not, she will drag it. She will lay one egg per cicada if the egg is left unfertilized.
Unfertilized eggs develop into males only. Fertilized eggs develop into females and are given at least two cicadas. Cicadas are then stuffed into the female’s burrow. Each burrow normally has three to four cells with one to two cicadas in each. However, it is possible for one burrow to have 10 to 20 cells. Eggs hatch in two to three days, and larvae begin feeding on paralyzed cicadas.
Feeding continues for four to 10 days until only the outer shell of the cicada remains. The larva overwinters inside a silken case. Pupation occurs in the spring. There is one generation per year.
Cicada killers are not dangerous, but they can be a nuisance. If you believe control is necessary, treat the burrows after dark to ensure the female wasps are in their nests. The males normally roost on plants near burrow sites. They can be captured with an insect net or knocked out of the air with a tennis racket during the day. Permethrin may be used for control.
There is still time to sign up for the Master Gardener program.....
.... so come on down and check it out. It is that time of year when we are taking applications for the Butler County Master Gardener Program. This year will be as rewarding as ever; we will be training with Reno and Harvey counties. What a mix; I always get a charge out of the wide variety of people that pursue becoming a Master Gardener. It seems as if there are always new interests or new twists to gardening that I haven’t got around to considering yet.
Coming up real soon is another reason you may want to consider the Master Gardener Program, and that would be the opportunity to attend Advanced Master Gardener training at K-State. This year it will be held over three days in early October with more than 40 different classes offered in a wide variety of more specialized interests. This generous offering of advanced classes is only available to those who have gone through the basic Master Gardener curriculum at the county level and completed their commitment to the program.
Page 3 of 3 - This year our basic Master Gardener training includes soils, herbs, tree I.D., water gardens, plant propagation, indoor plants, lawns, landscaping and fruit and vegetable gardening along with basic botany, shrubs, annuals and perennials, insects (both good and bad), and critter control.
So it’s time to get that application filled out for the Butler County Master Gardener class. I will accept them up to Aug. 31, and classes start Thursday, Sept. 13.
The training will be every Thursday (except Oct. 18 and and Thanksgiving) from 9 a.m. until 3:30 p.m. The cost is $100 per person.
So call the office at 316-321-9660 to get your application or have one sent to you, and I’ll see you in the garden.