Thursday, July 31, 2008

Fall webworm

Looked at walnut trees lately? The one’s I’m observing have large white webs at the ends of their branches. This is a common sign of an insect called fall web worm that begins feeding about this time of year. By late summer these webby nests will engulf large portion of the limbs. It’s unsightly but not a big deal because they feed so late in the season that the trees have already stored lots of energy to sustain themselves. So, the webbing is ugly but not cause for alarm. I see them in wild cherry trees, too. Sassafras, persimmon, sweetgum and about 200 other deciduous tree species are host plants for this insect.
Inside the nests you’ll find pale yellow, hairy caterpillars with black dots on the back. When disturbed they may begin to jerk around rhythmically in a defensive posture. Pretty cool. Many parasites and predators keep the population in check… in the long run.
If you can’t stand the look of them, you can simply cut of the offending branch. But most of the time it’s way up in the canopy of the tree, beyond reach. Insecticides will kill them but pruning is a more selective, reasonable choice if you have to do something. And remember that this is mostly a cosmetic problem, not a tree health problem.

Thursday, July 24, 2008

Tomato Troubles

Most gardeners are starting to harvest tomatoes by now. Some have been at it for a month. So, here at the Penn State Extension office, calls about tomato trouble are starting to come in. Want to see gory pictures of tomato problems? Check out Penn State and our sister institution Texas A& M for some exquisite shots.

This week I saw the following:
Early blight, the most common fungal disease of tomato. It causes lower leaves to turn yellow then brown. On closer examination you’ll see brown spots with concentric rings of dead tissue. Later, tomato fruit will develop rotten spots. Staking plants to improve air circulation and quick drying is an important control measure. Fungicides work very well but most gardeners are not interested in spraying plants and despite the infection, plants usually produce a decent crop… for a few weeks. The fungicide chlorothalonil is effective in preventing the disease spread and is available over the counter in garden centers. Organic gardeners can use copper fungicides and get limited control.
My strategy: 1) Stake ‘em up early and often 2) have a second planting coming on and abandon the first when the disease overwhelms them in late August. Go ahead and compost that old stuff.

Blossom end rot causes a dry, leathery, brown rot on the blossom end (opposite the stem end) of fruit. Caused by calcium deficiency. Hard to fix now. Soil test and add needed calcium with lime or gypsum in the fall to boost Ca levels for next year. A Penn State Soil test will tell you how much. Sometimes blossom end rot shows up in gardens with adequate calcium. Anything that prevents the plant from absorbing calcium from the soil, such as moisture extremes or root damage can result in blossom end rot. Sometimes plants have affected fruit for a while and then snap out of it.

Viral diseases mimic herbicide injury. Saw several cases last week. My guess is cucumber mosaic virus but that is just an educated guess. Viral diseases cause weird plant distortion and mottled, mosaic patterns (several shades of color) on fol age and fruit. Fruit are often undersized and misshapen. Viral diseases are a tough case because there is no cure. The virus lives in other plants, often hundreds of species, including ornamentals and weeds and is transmitted by insects such as aphids and leaf hoppers. They can even be transmitted by human handling of infected plants. You may see viral symptoms on beans and vine crops also. I do not know why virus diseases are devastating one year and almost non-existent in another. This is looking like a good year for viral diseases.

By the way, none of these problems make the tomatoes inedible, just cut out the affected parts and chow down. And another thing….aren’t you glad that your paycheck isn’t dependant on your horticultural skills and Mother Nature. That’s the high risk game farmers are in.

Wednesday, July 23, 2008

Plan now for fall harvest

By now many vegetable gardens have gaps… places where early season crops such as lettuce, peas, beets and other quick maturing crops have come and gone. If you like the idea of broccoli on Columbus Day, cauliflower at Thanksgiving and home grown carrots at Christmas you’ll need to make preparations now. Hey, maybe you are a slow starter and are just now getting around to breaking garden ground. In any event, there is plenty of growing season left in 2008.
Many of our favorite vegetables are cool or cold tolerant. Frost and even a hard freeze are not a problem. It’s true that growth slows during cool, short days of fall, but if those plants have had a good head start you will be rewarded.

So, take a look at your seed inventory, visit garden centers or jump on-line for seeds of lettuce, broccoli, cauliflower, carrots, beets, leafy greens and other cool tolerant crops. Then get those garden areas worked up, fertilized and seeded. You will also see transplants of the cabbage family crops showing up in better garden centers about now. Obviously, with transplants you can start later…into mid August.

One of the beauties of fall gardens is that crops “hold” well. Broccoli heading in June has a short life. Broccoli heading in October will hold tight for a long time. Same with cauliflower. Brussels sprouts anyone? The root crops (beets carrots) are also great fall vegetables. Leave those carrots in the ground after the tops die down and much with straw. Then go digging at Christmas and see what you’ve got. They make great stocking stuffers.

Maybe I’m nuts to be thinking about fall frost when it is 98 degrees but let’s see who’s laughing in October when the harvest is on. For a Penn State has a great fact sheet on growing leafy greens. Check it out.

Thursday, July 17, 2008

Wineberry... friend or foe?

One of Buck Shorts devoted readers commented recently about wineberry, Rubus phoenicolasius. Quite a coincidence since I had nibbled on it a few just hours before. We’ll, maybe not so much of a coincidence because this wild bramble is bearing lots of fruit right now and many folks enjoy it.

Wine berry looks a lot like other brambles such as red and black raspberry except that it is covered with sticky red hairs and bristles rather than sharp prickles. The fruit are a bit smaller than other brambles but they are very tasty and distinctly “wine colored”. I know wine comes in many colors so let’s call wineberries a deep rosé. They are bearing now, after red and black raspberries but before the blackberries.

One of the nice things about wineberries is that they grow wild and if you know where to look you can just graze on them every year. No gardening necessary. A few popped up in my yard last year (deposited by seeds in bird droppings, no doubt) and I let them grow. Like most brambles, the canes are biennial. Year one, canes are vegetative; year two they bear fruit and then die. Besides the nice fruit, they are kind of pretty, too.

I did a quick
internet search on this plant and learned that it is not native and is considered invasive in many states. It was introduced as breeding stock and is native to China, Japan and Korea. Wineberry is on Massachusetts’s and Connecticut’s noxious weed list. Many sites describe its invasive nature and I believe that it is capable of displacing native vegetation. So, in some states at least, if you cultivate Rubus phoenicolasius you are breaking the law. The weed police will not bother you in Pennsylvania, so pick away. You can even say you are doing your part to prevent its spread if you beat the birds to the seedy fruit. In any event, you only have another week or so if you want to enjoy the wineberry crop. Take a walk in the woods and you may find some.

Want to learn how to grow your own brambles? Check out
Penn State's guide to growing fruit in the backyard. It has an entire chapter on brambles.

Hey Kathleen, thanks for the photo of Rubus phoenicolasius. Love the images on
your photoblog. And Buck Short says thanks for his new image posted on this site.

Tuesday, July 15, 2008

Penn State College of Ag Sciences… more than you think!

OK, I’ll admit up front that I am a bit biased because I work for Penn State but I think you will agree that there is more to the Penn State ‘s College of Ag Sciences than you thought… after you take a closer look.

You can take a 200 mile drive west and visit the place. But many of you will find it easier to just check out the web-based resources at You won’t be able to smell the manure, see the flowers, or hear the roar of the Nittany Lion from your desktop but it is still pretty impressive.

The welcome page at the College’s site highlights some current activities. Did you know there was a natural gas rush going on in parts of Pennsylvania? Penn State is playing a role in protecting landowners from being rushed into a poor decision. Are you really into Agriculture? Learn more about Penn State annual Ag Progress Days which will be held in late August. Agricultural research is showcased at this event.

One of the best features of the site is the search box that allows you to mine the depths of the College’s resources. Just for fun I typed in “tomato’ and found fact sheets on growing, canning and staking tomatoes. I also found nice color pictures of tomato diseases. I’ll be talking to you about early blight soon. Stay tuned. Back at the home page I see that Penn State is helping farmers in Nepal manage tomato and eggplant disease.

Next I typed in the word “pond” and found Penn State’s pond website. Besides all of the nice publications and pictures, I learned that an on-line pond management course will be offered this fall. Wow! Penn State Ag Sciences… more than you think!

Thursday, July 10, 2008

Watch Your Ash

The other day I found myself taking a cross country walk through suburban Doylestown Township. From Cross Keys to Delaware Valley College, if you know the territory. I was trying to stay out of the sun so I stuck to the side streets, looking for shade. I found a lot of shade but as I proceeded though one particular development I noticed something disturbing. Almost every tree I walked under was ash. Green Ash is a great tree -tough as nails and well adapted to our region. Not much for flowers or fruit but it's a good choice for shade. Or it was.

As you may have heard, there's a new pest in Pennsylvania called Emerald Ash Borer. Just about one year ago the pest was found on the western Pennsylvania border. It traveled east from Ohio. The original infestation in the United States was found in Michigan in 2002 where it has devastated more than 30 million ash trees. Who knows how long it will take for this boring beetle to reach our end of the state but experts agree, it is just a matter of time. The larval stage of this insect destroys the water and nutrient conducting tissue just beneath the bark, causing trees to die. Symptoms include back cracking, woodpecker activity, crown die-back, and ultimately , tree death. Several other borers attach ash. Check symptoms to distinguish between them.

So, as I enjoyed the shade of these fine trees I could not help but think that some day they are likely to be wiped out by a new invasive pest. Forget about eradication. This cat is out of the bag. Individual ash trees will be candidates for insecticide treatment but wholesale protection of woodland trees and most landscape trees is just not feasible. Don't panic now and call the arborist. We'll have more specific instructions when it finally gets here. No sense in treating trees before the bug is here.

For now, enjoy the shade. Think twice before planting ash (we're talking the genus Fraxinus not mountain ash, Sorbus). Be glad that Pennsylvania has only a modest amount of ash in it's forests and landscapes. It may be many years before eastern Pennsylvania deals with this pest. Regulatory agencies are monitoring throughout Pennsylvania to track it's progress. If you happen to see a big purple box hanging in an ash tree, this is one of the monitoring stations.

Click on the Emerald Ash Borer link above to get the full story. You can follow the progress of this insect and read it's history from this site. And watch your ash.

Thursday, July 3, 2008

The Beetles Reunite for 2008 Performance

Back by unpopular demand for the 92nd year... The Beetles (Japanese Beetles)! Performances began the last week in June and are scheduled throughout the region for the next 30-45 days. Their tune has not changed much. Expect them to be playing Skeletonizing Zinnia, Happiness is a Warm Raspberry, Lovely Rosebush, Grape Leaf Surprise and others among their repertoire of 300 favorites.

By early August, the aging group's offspring, calling themselves The Grubs, are expected to go underground. The new generation will perform, as usual, on (actually under) lawns. They prefer well irrigated turf and usually are a bust if dry weather prevails during late summer. So, if this group's act is not for you, allowing lawns to remain dry is a good way to reduce their presence.

Certain homeowners have taken preventative measures against both the adult and expected juvenile stages of The Beetles by calling The Police who applied very effective chemical controls in the form of imidacloprid to trees, shrubs and lawns. It's too late for this treatment on woody plants but lawns can be treated through the month of July if many Beetle performances occur in your area. Be sure the treatment is watered-in after application.

On thing I've noticed is that once performances begin, they tend to keep playing in the same site for a long time. So eradicating Beetle infestations early is important. Trapping beetles is easy but ineffective. They can fly. A popular control measure used on the The Grubs, called Milky Spore Disease has not proven effective in research studies, according to many Beetle experts. Old timers are known to apply The Hand Jive to control beetles. Catch them napping early in the morning and knock them into a can of soapy or oily water.

Successful tours the past two years may be catching up on the Beetles. Rival groups, including The Wasps, The Flies and even the Birds and The Toads are taking their toll on The Beetle's success.