Pruning Blueberries: Fact & Fiction
(Continued from page 2)

over also tend to produce an upright shoot.  These canes should be pruned just above this upright shoot to produce a more erect plant.  Other varieties which often fit into this category are Berkeley, Bluetta, Coville, Weymouth and Patriot.  Varieties such as Bluecrop, Collins, Darrow, Earliblue, Herbert, Jersey, Lateblue and Elliot often fall into the erect plant category.  These plants become overly dense in the center, which decreases fruit bud initiation.  The pruning strategy for this category is to remove older central canes before all others.

When plants are overly vigorous, the primary strategy is to remove entire canes rather than spend time on detail pruning.  This is done at least until the proper fruit to cane production balance can be established through nutrition and fruit production management.  Varieties which are prone to this situation are Earliblue, Blueray, Herbert and Collins, though any variety can potentially be overly vigorous.

Weak plants are treated in the opposite manner.  The primary procedure is to detail prune rather than to eliminate whole canes. Varieties which are classically put into this category are Weymouth and Bluetta.

I should take a moment to address the method of pruning on a field which has been neglected for a long time and needs to be rejuvenated.  This question often comes up when a grower has purchased one of these fields.  The most important step is to inspect the plants in their field for virus symptoms.  Any plant showing these symptoms should be pulled out.  The plant inspections must be done during the growing season because symptoms are most easily seen on the leaves.  The next step is to completely prune everything down to the ground (a chain saw is the quickest and easiest method).  This pruning is best done in late winter.  An application of a 10-10-10 fertilizer should be made in early April, usually at a rate of 400 lb per acre.  No crop will be harvested that year.  However, the following winter the canes should be thinned to approximately 12-16 canes per plant.  A full crop can be harvested that year. 

In summary, pruning correctly can:

• increase yield, by producing more young canes
• increase fruit size by producing more strong wood
• decrease disease by removing dead wood
• increase cane initiation because as pruning increases, cane number increases
  

Consider Crop Rotation
Kristen Wilmer, University of Connecticut

While crop rotation is one of the oldest tools for managing pests and its benefits are widely acknowledged, it is frequently overlooked as part of an integrated pest management program.  Given the variety of production and marketing constraints that each farm faces, it can be challenging to successfully incorporate crop rotation into your farm operation.  The following discussion is intended to help you better evaluate the benefits and costs of crop rotation, and to determine the overall practicality of various rotation systems on your farm.

The Benefits of Crop Rotation

1) Rotation controls disease--By far the greatest benefit of vegetable crop rotation is disease control.  Planting the same crop or related crops in a field for multiple years frequently leads to a sharp increase in disease pressure.  Consider the following two examples from a study at Penn State University:

• Defoliation from early blight at the start of harvest increased from 3% (in the first year) to 30% (in the second year) to 74% (in the third year) in continuously cropped tomatoes.
  

• The onset of Alternaria blight occurred three weeks earlier in the fifth year of continuous melon production than it had in the first year  (advancing by about five days per year).
  

Including carefully planned rotations in a pest management program can help reduce or eliminate the majority of vegetable diseases.  Most plant pathogens can survive only for a short period outside of their host, so rotating a field to unsusceptible crops reduces the number of pathogens that persist in the field.  Rotation is especially important for diseases that can't successfully be controlled by other methods.  Diseases that require rotation for effective control include Phytophthora; Plectosporium blight; scab; bacterial canker, spot and speck; early blight; black leg and black rot; clubroot; anthracnose, Sclerotinia white mold; Fusarium crown and fruit rot, and a variety of root rots.  Thus, crop rotation can lead to more effective disease control while at the same time reducing the cost, labor requirement and environmental impact of pesticide applications.

2) Rotation reduces weed pressure--Rotation is also helpful in suppressing weed populations.  Planting the same crop in a field for multiple years creates a relatively stable environment for weed growth.  Because herbicides applied and tillage times remain fairly constant, weeds that are adapted to the particular conditions maintained for that crop tend to thrive.  This can occur even in crops with good weed control, as in the case of atrazine-resistant