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Sightings from the field: Week of July 29th

We're adding a new column to the newsletter called "Sightings from the field". Since our team does regular farm visits, we see a lot of diseases, insects, and nutrient issues, but also a lot of cool and exciting things! By sharing what we're seeing on farms around the state, we hope that you'll appreciate an inside look at what other farmers are dealing with, and the creative approaches they're taking.

This week: July 29th. Natalie and Annie were up on the iron range visiting farms, so many of our photos this week come from the far north.

Chimera, Aitkin County

Photo: A chimera on pepper. 
Natalie Hoidal
This one had us stumped at first. The grower had a row of peppers in the field, and about half of them were showing this streaking pattern on both the leaves and the fruit. We considered herbicide drift (not likely given the situation), a nutrient deficiency, or maybe even "burn" from an over application of fertilizer.

It turns out the streaking was caused by chimera, a genetic mutation that causes chlorosis in certain cells. Chimera is actually intentionally bred for in the ornamental industry (think variegated plants), we even found a bell pepper variety intentionally bred to have chimera, called Striped Holland Bell Peppers.

Cabbage worms,  Everywhere!

There are three main cabbage pests in the Lepidoptera family, the Diamondback Moth, Imported Cabbage Worm, and Cabbage Looper, and they are in full swing across the state. Diamondback moths were pupating in northern Minnesota this week, meaning they'll soon be emerging as adults.

Cabbage Loopers and Imported Cabbage Worms were still in the larval stages, where they're more easily controlled with Bt insecticides (a couple of Bt insecticides are approved for organic systems). Depending on your scale, it may also be practical to simply squish the larvae, which can typically be found on the undersides of leaves.

Various tomato diseases, Dakota County and Le Sueur County

Photo: Early Blight, UMN Extension
Tomatoes can be impacted by a whole host of diseases at this time of year. If you're seeing disease pressure in your tomatoes, a good place to start for identification is the "What's Wrong with My Plant" tool.

However, diseases can be very difficult to distinguish from one another just by sight. Consider sending samples to the Plant Disease Clinic for a proper diagnosis - knowing exactly what's causing symptoms will help you to manage it properly, and can give you valuable information about what types of disease resistance to seek out when choosing seeds next year.

Pumpkins in the pipeline, Cambridge, MN

Photo: Tan pumpkin variety in our trial.
Annie Klodd, UMN Extension
Annie Klodd is partnering with Rod's Berry Farm near Cambridge, MN on a 40 bin count (medium sized) pumpkin variety trial this season. We are comparing 32 varieties total, including classic varieties, newly released varieties, and varieties that are still in the research pipeline.

They are grown on minimally-tilled land that is used for strawberry production for several years before being rotated into pumpkins and rye. Pictured here is a new, tan colored jack-o-lantern style variety. Seed is provided by Rupp Seed, Sakata Seed, and Harris Moran Seed.

Yellowing leaves on pumpkin, Cambridge, MN

Photo: Leaves with yellow edges.
Annie Klodd, UMN Extension.
Yellowing leaves on pumpkins are not always a result of diseases or insect problems, stressing the importance of considering all possibilities and looking at your soil test, weather, and spray program before diagnosing a problem. Often, yellowing along the edges of pumpkin leaves can be a sign of water stress or other abiotic factors.

Even though this has been a wet season, parts of Minnesota with sandier soil may expect water stress symptoms on pumpkins following just a few days of dry weather, especially when the plants are large and have high water requirements to grow sizable fruit.

A nice example of a high density apple orchard, Aitkin, MN
Photo: Annie Klodd

Lastly, we visited Gilby's Nursery and Orchard near Aitkin, MN. This orchard is a nicely managed example of a high density dwarf apple planting. Their newest orchard has trees spaced 3 feet apart, on 8 foot tall trellis.

While many Minnesota orchards are still planted with traditional spacing and semi-dwarf trees, high density is what many orchards in larger apple regions are moving toward. High density plantings greatly improve efficiency by allowing for easier harvest and pruning. In high density plantings, the trunks are trained to trellis wires, and often the limbs are replaced regularly, being pruned off after they reach about four years old. Click here for more information on high density apple orchards.

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