Avoid planting the same bean in the same field year after year. Rotating to a nonhost crop can significantly reduce pest numbers in the field. Nonhost crops are crops that cannot support a specific pest or pests of dry beans. The table below provides information on nonhost crops that interrupt certain dry bean-associated pathogen, nematode, and weed cycles. In general, avoid leguminous crops as rotation choices for beans.
Although the longer nonhost crop rotations suggested in the table below are ideal, they may not be economically feasible. A rotation of shorter duration is still beneficial but to a lesser degree.
Use the table below to help identify appropriate rotational crops and time for different pests in your field.
|Pest type||Suggested crop rotation cycle (years)||Nonhost crop options and other comments|
|Ascochyta blight (garbanzo beans)||2–3||Ascochyta rabiei, cause of Ascochyta blight on garbanzos, is specific to garbanzos, so rotate to any other crop.|
|Bacterial brown spot||2–3||Corn, cucurbits, onions, tomatoes|
|Bean anthracnose||2–3||Nonlegume crops, for example corn, cucurbits, onions, tomatoes, safflower|
|Charcoal rot (Ashy stem blight)||2–3||Cereal crops, except corn and sorghum|
|Common bacterial blight||2–3||Nonlegume crops|
|Halo blight||2–3||Nonlegume crops|
|Fusarium root rot||3||Pathogen survives well without bean hosts, so rotation will not solve problem entirely, but cereal crops are the best choice.|
|Fusarium wilt||(>5 years)||Pathogen survives well without bean hosts, so rotation will not solve problem entirely. However, any crop but the bean variety that the species of Fusarium attacks may help. Plant garbanzo and blackeye varieties that show resistance to this disease.|
|Southern blight||2||Corn, small grains, safflower|
|White mold||2–3||Corn, small grains, safflower|
|NEMATODES—If your field has a history of nematodes, destroy volunteer beans. Most common weeds are hosts, so rotations should be weed free.|
|Javanese root knot nematode (Meloidogyne javanica)||2–3||Resistant tomato varieties; winter small grains followed by fallow period during summer; resistant varieties of Acala cotton, baby limas (Cariblanco N, Beija-Flor), blackeyes (CB-50, CB-27)|
|Southern root knot nematode (M. incognita)||2–3||Resistant tomato varieties; winter small grains followed by fallow period during summer; garlic, onions; alfalfa; resistant large limas (UC 92, UC White Ventura N) baby limas (Cariblanco N, Beija -Flor), blackeyes (CB-5, CB-46, CB-50, and CB-27)|
|Summer weeds||6 months to 2 years, dependent on herbicide plantback||Tomatoes, melons, cotton, and corn, selective herbicides, and cultivations. Plant into moisture as opposed to irrigating crop up to minimize weed pressure.|
|Winter weeds||1–2||Cereal crops and suitable herbicides|
|Perennial weeds||2–3||Cereal crops, summer fallow, herbicides|
For additional information on crop rotation, refer to the following manuals: