Weeds
As a short statured crop, dry beans are not very competitive with weeds. Since they are often planted in June, there is time to do a tillage pass a couple of weeks before planting to sprout weeds, then come back right before planting with additional tillage to kill those weeds. Drilling the crop in narrow rows can also help with weed control. There is a fairly long list of herbicides* labeled for dry beans, including: Assure II, Basagran, Dual, EPTC, Frontier, Lasso, Outlook, Paraquat, Poast, Prowl, Pursuit, Roundup, Select, sodium chlorate, Sonalan and Treflan. Check the product label to confirm that dry beans are covered and has guidelines.
Insects
There are several times when insect pests can cause damage to dry beans. Weekly scouting of fields is recommended. Like soybeans, dry beans are susceptible to bean leaf beetle, other leaf feeders and cutworms during establishment. Usually, the dry beans can tolerate up to 50% defoliation for a short period in the seedling stage, and still bounce back nicely. As the plant develops, white flies may briefly infest the crop, disrupting plant tissues and causing wilting and stunting of foliage; whiteflies also have the potential to introduce a virus to the plants. Later, as pods are developing, various sucking insects, such as stink bugs, can damage pods and the appearance of seeds. Since seed appearance is much more important with dry beans than with soybeans, pod and seed damage must be monitored closely. There are about 40 insecticide products labeled for dry beans, along with some organic materials such as pyrethrins that can work well.
Diseases
Dry beans are more susceptible to diseases than many crops, especially in a humid climate like Missouri’s that can have extended wet periods. Viruses, fungi and bacterial diseases are all potential problems. Once a virus or bacterium attacks, there is nothing that can be done, but certain fungal diseases can be treated with one of the 30 fungicides labeled for use on dry beans. Bean rust, which shows up late in the season, and white mold, a rotting disease in wet years, are two serious diseases of dry beans that can be controlled by fungicides. Some viruses can be prevented by an IPM approach to controlling the insect vectors, such as white flies, that can introduce the virus.
Disease control strategies to use with dry beans include selecting resistant varieties, rotating crops, and scouting for white flies or aphids that can introduce a disease. Avoiding poorly drained soils can also help prevent fungal diseases. Bacterial blights, which are seed borne, may be avoided by selecting only certified, high quality seed; using bin run dry beans for seed is not recommended, since they may carry blight or other diseases.
*Pesticides mentioned as being labeled in this publication are based on reference lists published in the Thomson Publications “Quick Guide” on crop pesticides, 2002 edition. These lists are believed to be accurate, but given the changing nature of pesticide registrations, labels and relevant government pesticide regulations should be checked before applying any herbicide or other pesticide.
Harvest and Storage
Bush-type cultivars can be harvested with the same equipment as soybeans. Flexible cutter bars are helpful in getting closer to the soil, since dry beans tend to have pods very close to the ground. Rotary combines reportedly do a good job with dry beans. There are specialized dry bean combines available that have two cylinders made to get good seed cleaning without seed breakage.
It is important to keep in mind that dry bean seed appearance is very important to the price obtained for the crop. Besides the normal seed cleaning, dry beans may need to be polished using tumbling drums or other devices to obtain full value. Both swathing and direct combining are used with dry beans: the preferred approach depends on the growth characteristics of the cultivar, and the potential for rain damage on windrowed beans.
Harvest can start when seeds are at 18% moisture. This is generally when some pods are brown and a majority of pods are yellow. Cylinder speeds at high moisture can be 300 to 450 rpm, but the cylinder speed should be slowed down with drier seeds. Sieve setting should be 7/16 of an inch, with relatively high fan speeds. Concaves should initially be set 1/2 inch at front and 1/4 inch in the rear, and opened up further as the beans dry down. The combine’s operating manual may have suggestions on settings for dry beans. If beans are cut when the pods are getting really dry, seed shatter can become a problem. Cutting at night or when a dew is on can help reduce shattering.
One caution for harvest in Missouri is that rains at the time of harvest can cause discoloration in the seed, especially of a navy (white) bean type. This is one reason that drier regions in the Great Plains, California and Pacific Northwest have had a competitive advantage with dry beans. Harvest should be done quickly to help avoid discoloration. Choosing a dark seeded variety or pinto variety can help minimize this problem.
Seeds should be stored at about 15 to 16% moisture. When handling, a belt conveyer is recommended over a metal auger to reduce seed damage. Seeds should be handled gently and not dumped from heights onto concrete or hard surfaces. Careful handling may be more time consuming but will pay off in the price received for a quality bean product.
