June 23, 2009
Tomatoes Not Setting Fruit
Well, it seems as if some gardeners around the state are having trouble with their tomatoes not setting fruit. So far, that has not been an issue at my house. But my friend, Chuck Browne, the county Extension coordinator in Lee County has some thoughts on what might be the problem for these folks. Check out his guest blog below.
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Many of you have called our office saying that the flowers on your tomato plants up and fall off without setting any fruit. You are probably hoping that I have an answer for you that will stop this problem.
First, the good news is this condition is not related to any nutritional disorder or any disease or insect damage. It is related to temperature. Despite that tomatoes evolved in the tropics, flowering in tomato is sensitive to temperature. When day temperatures exceed 85 degrees F and night temperatures exceed 72 degrees F, tomato flowers will abort. An important factor involved with temperatures is this, the longer the condition lasts, the more serious the effect on flowering. Short exposures such as a week or less should not cause much of a problem. Although the combination of high day and high night temperatures causes blossom drop, high night temperatures alone can be detrimental to flowering even if day temperatures are not higher than 85 degrees F.
Now here’s the bad news. Older or heirloom, home garden varieties, which are most popular among home gardeners, are more sensitive to high temperatures than many of the newer hybrids that are presently available. When fruit do not set and all other conditions are otherwise favorable (e.g., sufficient water and fertilizer, good pest control, appropriate pH), plants generally become vigorous and dark green. Even new hybrids, however, are susceptible to blossom drop.
Commercial growers in the southeastern United States have suffered with this problem for many years until the recent advent of “heat set” tomato varieties. These varieties have been bred for tolerance to high day and night temperatures common in the summer and early fall. In fact, many of these varieties set fruit under poor growing conditions-extended cool, rainy periods as well as during extended periods of hot weather.
What to do: For this year or for an existing planting, keep the plants healthy. Keep plants watered. Maintain fertility levels and control any pest problems as any additional stress will make the condition worse. The plants will produce flowers and set fruit when temperatures become more favorable.
For next year, try growing a heat set variety. Many seed catalogs carry a wide range of tomatoes. Read the descriptions carefully looking for phrases such as heat set, hot set or heat tolerant. Often these varieties have references to their heat tolerance in their names. Varieties such as ‘Sunbeam’, 'Sunmaster’, ‘Suncrest’ and ‘Sun Leaper’ have performed well in Alabama even during during extended periods of hot weather and have become a mainstay for many of our commercial tomato growers.
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You can find more information on tomato production and blossom drop from the Alabama Cooperative Extension System here and here. This publication from Clemson University Extension has a lot of good information.
June 16, 2009
Battling Bugs Safely
Insects have been the topic of my last several blog entries. Wel,l if you are battling bugs and have decided to turn to insecticides whether they be conventional or organic, and, yes, there are organic insecticides, give a listen to my most recent Backyard Wisdom program with Dr. Fudd Graham, who is an entomologist at Auburn University. You will find it here.
June 12, 2009
The Ugly Continues
Well, it seems I am not the only one in Alabama suffering the onslaught of Japanese beetles. My friend, Greg, who is also an Alabama Master Gardener, has found them on his roses and has begun his control efforts.
I also noticed for the first time near my office on the Auburn University campus that a Japanese beetle trap had been hung in a maple tree.
Also two friends and regular guest bloggers here at Backyard Wisdom, Danny Cain and Chuck Browne, wrote about them in their weekly Extension columns for their local papers. Both Chuck and Danny are seeing them in their respective counties. If Japanese beetles are present in both Lee County in east central Alabama and Walker County in the northwest part of the state, you can bet they are being seen almost statewide.
You can see Danny’s column here on the Alabama Cooperative Extension System’s Home Grounds blog. Near the end of his column, Danny has some interesting thoughts about using Japanese beetle traps. He and others agree that the traps which use pheromones to attract beetles seem to lure more beetles than they trap, leaving your vulnerable plants ready for attack from these untrapped beetles. Research at the University of Kentucky has confirmed this.
So for those of you battling Japanese beetles, find a control that works for you. Also if Japanese beetles are a yearly problem for you, do your research on how to control the white grub stage of the beetle. A good first step is to read this publication on Japanese beetle control written by one of Alabama Extension's regional home grounds agents, Shane Harris. In Alabama, you can get more information on this from your county Extension office or your regional Extension home grounds agent.
June 11, 2009
The Good, the Lovely and the Just Plain Ugly
Today in my garden, I saw a variation on that Clint Eastwood movie, “The Good, The Bad and the Ugly.” But for me, it was the good, the lovely and the just plain ugly. You are probably wondering what I could be referring to.
Basically, I’m talking about insects. Yes, bugs have been on my mind a lot since my quest to identify the woolly aphid on my eggplants.
The Good: I saw a good variety of beneficial insects at work. Assorted bees were busy in the beds near my birdbath. Salvia ‘Black and Blue’ in particular was drawing a large number of bees. Lady beetles have settled in around my container vegetables and seem to be controlling both those woolly aphids and the more common green ones. You will find a good discussion of beneficial insects in Alabama here and here.
The Lovely: I don’t think that another shrub has a more appropriate common name than butterfly bush. Butterflies were in good numbers on all of my eight large buddleias. I saw viceroys, swallowtails and variegated fritillaries, I think. My identification skills on butterflies are not top notch. I am hopeful that my recently planted dill and parsley will lure some black swallowtails to lay their eggs. For more information on bringing more butterflies to your garden, check out this publication from the Alabama Cooperative Extension System.
The Just Plain Ugly: It really was too much to believe that I would not find some insect pests as I wandered in my garden. But, really did it have to be Japanese beetles? I don’t think there is an insect pest that I dislike more than Japanese beetles. Not only do they attach my roses, but they also love to chew on my double pink Rose of Sharon.
Fortunately, I didn’t see that many of those pesky iridescent beetles so I think I will start with a coffee can with an inch or so of warm, soapy water that I can thump the beetles into. If that isn’t enough, I will look for some solutions here.
Then, if Japanese beetles were not enough, there was brown scale making itself at home on my Buddha’s Hand citron and ants busily harvesting the honeydew secretions from the scale. It appears that I have caught that pest early so I think wiping down the infested areas with a wet cloth may do the trick. But I’ll have to keep a watchful eye to make sure it doesn’t spread. If it does, I will have to use an insecticidal soap to bring it under control.
Lessons to be learned: First, improve your insect identification skills. That will allow you to identify beneficial insects as well as insect pests. Then, choose your control methods wisely. I try to use mechanical and other organic options before choosing synthetic controls for two reasons. First, mechanical and other organic options have less impact on the beneficials I want to keep. Second not only am I a lazy gardener, I am a cheap one. These options are usually a cheaper control method, but not always.
June 02, 2009
Name That Bug!
Never underestimate how much attention a small insect can demand. I was working in my garden this weekend and noticed a strange fluffy white insect on an eggplant. I tried to crush the tiny critter between my thumb and forefinger, but it jumped---hopped---or flew quickly to a new spot.
Then I noticed the same insect on my Buddha’s Hand citron tree located on the other side of the house.
By the next day, the one or two on the eggplant had increased to about a dozen.
Now I’m annoyed and I want to know just what this insect is. It’s white and fluffy like a mealy bug, but it moves way too fast to be one of them.
I pull out Dr. Whitney Cranshaw’s book, “Garden Insects of North America,” but I don’t see this insect. On Monday, I call one of my best county Extension agent buddies and describe the insect to him. He suggests it may be an aphid.
An aphid? Who ever heard of an aphid that looks like a tiny cotton ball?
Well, I can’t let it go so I launch a full-scale Google search attack using a variety of words to describe the insect. At some point, I added the word woolly to the search string. Lo and behold, I think that I now have my answer. It is probably an adult woolly aphid. Check out the photo at Iowa State's Department of Entomology site.
It’s also settled the tiny insect’s fate at least on the eggplant and the citron tree. Because aphids can act as vectors for different plant viruses, I plan on giving both good blasts of water to wash the aphids off. Then, I hope the lady beetles I noticed on the eggplant and nearby tomatoes will polish off any of the remaining aphids.
Identifying the insect pest allowed me to determine how best to manage them. Those are two critical elements of integrated pest management or IPM. I am combining a mechanical means of control, hosing off the plants, and a biological control, letting a natural aphid predator do its job.
If you want to learn more about IPM, visit the Alabama Integrated Pest Management Information Center or the Enviromental Protection Agency’s fact sheets on IPM.