This week in MSL radio garden world: bee colony collapse, basil leaf spot, underground bees, flies stuck on plants, and split lines on tomato shoulders. Sheesh, what a week! Click below for all the gory details...
Summer rolls on, and as the garden flourishes, so do the problems and puzzles. On Tuesday's Homegrown, we heard from a listener in Toronto, Canada, who grows zucchini to give out to her extended family. It seems the squashes her relatives rely on her to provide aren't setting fruit despite the hot weather. Tony and I thought it might have something to do with too much heat, and it turns out that squash, tomatoes, and beans may be considerably less productive in periods of high heat and humidity. We gardeners are always at the mercy of the weather, but I assured both our Toronto caller and a listener from Michigan who called on Wednesday that bushels of zucchini are no doubt in store as things cool down. Fortunately, the fruits mature so quickly that even in northern areas, you'll still have plenty to pick.
Our Toronto caller expressed grave concern about bee colony collapse, a dire situation indeed that seriously threatens the productivity of many major food crops. Andrew brought a little hope to everyone by mentioning the numerous universities and institutions around the world who are researching the problem. And while he was researching that, he came across the website Discover Life, a sort of online catalog of life on earth. There is so much great information and so many amazing photos here: Definitely one to bookmark!
Also on Tuesday we heard from a Washington, D.C. listener who came home from vacation to find her basil infected with ugly black leaf spot. It sounded to us like a classic case of bacterial leaf spot, but Clemson University in South Carolina tells us there are also three fungal leaf spots that can affect basil. In all cases, leaf spot is exacerbated by hot, humid conditions (which the caller confirmed, telling us "it's a swamp down here right now!"), so we encouraged her to cut back the spotty leaves, fertilize lightly, and try to provide good air circulation and the plant should outgrow it pretty quickly.
At the end of the show on Tuesday, Tony and I touched on underground bees which touched a nerve, since we heard from several listeners with underground bees. Carrie from Canada called me on Wednesday, telling Mario and I how she removed a hive from within her compost pile (!), relocated it under a shrub, and the bees continued to use it, even covering it up. Carrie wanted to know what kind of bees they were and if she could harvest the honey. Then on Thursday's homegrown, Bonnie from Michigan called and told the guys she also had underground bees. So, what is this mysterious insect? Turns out, several species of wasps, hornets, and bees sometimes nest underground. In fact, the familiar bumblebee usually lives underground in abandoned rodent dens. So how much of a pest a subterranean nesting bee, wasp, or hornet is depends on the species it is. Most wasps, hornets, and bumblebees only use their nests for one season, so if you can stick it out for the rest of the year, the problem will go away on its own. Honeybees, however, will be there to stay if their needs continue to be met. So Carrie, if you do indeed have honeybees, looks like you've got yourself a hive!
On Thursday morning, I heard from a listener in Michigan who had a very unusual problem: She had flies sticking to her plants, especially lavender, and dying there, as if cemented in place. I theorized that they had landed at the highest point on her plants in order to attract a mate and do their business, and having fulfilled their purpose in life, simply expired on the spot. However, I just found out that there is a fungus that can infect flies and cause them to stick to the surface where they die. Fascinating - if disgusting - business, and you can read all about it on Tom Volk's fungus page over at the University of Wisconsin (warning: contains verbiage that may seriously gross out sensitive individuals. Just sayin'). Cornell University further confirms that the fungus does indeed cause flies to stick to plants, too. Thanks for calling - I'm so glad I had the opportunity to learn about this! Not sure what you can do about the problem, but dead flies stuck to a plant outdoors beats a kitchen full of them any day, right?
Finally, Andrew and Tony heard from a caller whose tomatoes were cracking - and not in the usual way, from the bottom upward. These cracks were forming around the shoulders of the tomato in an arc-like pattern. Andrew referred her to our favorite (especially at this time of year!) Tomato Problem Solver. Like most cracks, this is probably a cultural issue and not a true disease or insect problem, but take a look at the photos to diagnose which disorder most closely resembles your problematic fruit.
And for all you gardeners, please visit us over at At Home in the Garden, where we talk gardening - the good, the bad, and the ugly - all the time. See you there!