Only about 20 days until we can eat the corn!
As a preventative for European Corn Borer, we’ve been spraying the silks every few days with alternating sprays of Bt and Spinosad.
Today when we arrived, we were panicked by the sight of one of the corn stalks covered in these black insects. They leaves and tassels were ensconced in these little black aphids. Strangely, out of the entire block of corn, it was only one plant that was infested. There are far too many to pick off. The debate quickly turned to whether we should cut the entire plant and remove it, spray, or just wait and see.
A bit of research revealed:
Aphids do not interfere with pollination unless most corn tassels are heavily covered with aphids and their honeydew secretions. Feeding by large colonies of aphids can reduce yields significantly. Aphid colonies can slowly kill the tassel and top few leaves of a corn plant. The plant responds by shunting nutrients to the feeding area and not to the developing ear, resulting in stunted ears or even barren plants. ( read more )
Further observation also revealed that they were not spreading. After a few days, the population reduced dramatically and the plant seems no worse for wear. It will be interesting if the yield is affected. It appears the worst case would be that we lost 2-3 ears of corn.
Today yielded carrots, lettuce, zucchini, summer squash, and (not pictured) 8 Red Norland Potatoes, Cilantro, and another head of lettuce
We pulled our first carrots (5 of them) today! In their place we put down more seed. We ate some of them raw and simply boiled the rest with a little salt. It is amazing what can come out of tiny little seeds.
July 23, 2009 Vegetable Notes Newsletter
In This Issue:
Crop Conditions
Late Blight Update
Managing Late Blight in Organic Potatoes
Alternaria Diseases of Brassicas
Cercospora Leaf Spot of Swiss Chard, Beets and Spinach
Sweet Corn and Pepper Report
Recap of the UMass Field Day
The new vegetable notes newsletter from The Agriculture and Landscape Department at UMASS Amherst is out!
In This Issue:
• Crop Conditions
• Late Blight Alert in Potatoes and Tomatoes
• Organic Fungicides
• Thrips in Onion and Brassicas
• Black Aphids in Greens
• Corn Report
• Upcoming Meetings
Download the newsletter here [PDF]
We continue to have a vandal destroying the leaves of some of our plants at night. As I mentioned before, the broccoli took a big hit one night and the prime suspect is a slug. They have moved onto the basil, eggplant, and a butternut squash. To trap (and kill) the assailant, I installed slug traps around the farm today.
They consist of an empty tin can filled with beer (left over from a venture into home brewing a couple of years ago) buried up to it’s rim in the soil. Since it has been raining just about every other day, I covered it with a flat-ish stone supported by four other stones. In theory, the slugs love smell of rotting/fermenting vegetation – which is essentially what beer is – and are attracted into the tin can from which they cannot climb out and drown.
Now we wait.
The three striped potato beetle is the insect pest of the past few weeks. Fully grown, they look something like this:
They appear harmless enough. In fact, when picked up they chirp which makes them rather endearing. Their young, however, have no redeeming qualities. Not only do they eat potatoes, tomatoes, and tomatillos, they have horrendous hygene habits.
They pile their excrement on their back in the name of self-defense. Yes, I am less likely to pick one up bare handed know this, but it didn’t make sense how this would protect them from other predators. Turns out the success of this strategy is linked to their choice of food.
These insects consume food that is full of harmful chemicals, but while they are constantly exposed to predators, their survival rate is very high. The frass-coated larvae Morton had noticed in Stony Brook were feeding on nightshade (Solanum dulcamara), a plant high in alkaloids–nitrogen-based compounds that are toxic to animals. Alkaloids include morphine, a derivative of poppies, and nicotine, a derivative of the tobacco plant. When the beetle larvae eat nightshade leaves, they absorb the useful nutrients and excrete the toxins, which are concentrated in their frass.
