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FIGURE 13. Virus-like symptoms in peas.
Photo:
Kevin
McPhee,
NDSU
Viruses that have been found with some frequency in peas in
North Dakota include PEMV and BLRV. Symptoms of BLRV
(also known as pea leaf-roll virus) in pea include interveinal
chlorosis, yellowing, stunting and leaf-rolling. BLRV is a
luteovirus, which means the aphid must feed for an extended
time to acquire and transmit the virus to new plants, so
insecticides to control aphids should be effective against this
disease. e pea aphid is the principal vector of BLRV. Other
aphids can also transmit the virus.
PEMV is one of the most important and destructive viruses
of lentils worldwide. It has been found in peas in North Dakota
and Montana. Symptoms include stunting of the plant, twisted
and malformed leaves, misshapen and poorly filled pods,
and growths (bumps) on the pod surface. Symptoms may be
confused with growth regulator herbicide damage. PEMV
is also transmied persistently by aphids, primarily the pea
aphid, cowpea aphid, green peach aphid, potato aphid, and
foxglove aphid. Insecticides may be effective. Generally, aphid
flights from other pulse-growing areas or neighboring fields
carry the virus, and aphids may not be seen until too late for
control to be implemented.
Other viruses which have been identified in legume crops
include Alfalfa mosaic virus, Bean yellow mosaic virus,
Cucumber mosaic virus, Pea seed-borne mosaic virus, and
Pea streak virus.
Variety selection is an important disease control strategy,
especially in areas that grow significant acreages of pulse crops.
Check with your retailer or county MSU Extension agent for
the best-adapted variety in your area. Some variety reactions
can be found in the Saskatchewan Ministry
of Agriculture's 'Varieties of Grain Crops' report at
www.agriculture.gov. sk.ca/Varieties_Grain_Crops.
Fungicide recommendations are available from several
sources. University sources include fact sheets on the High
Plains IPM guide (hp://wiki.bugwood. org/HPIPM),
AgAlerts, presentations, and your county agent. Your fungicide
salesperson also has information. Another good source for our
region is the NDSU Fungicide Guide at hp://www.ag.ndsu.
edu/ extplantpath/publications-newsleers/fungicides and
the Carrington Research Extension Center website at hp://
www.ag.ndsu.edu/CarringtonREC/agronomy-1/ copy_of_
crop-index/plant-pathology. e majority of the chemicals
registered in North Dakota are registered in Montana, but
always check the label. Section 18 and 24c (local) registrations
are available on the Montana Department of Agriculture
website at hp:// agr.mt.gov/agr/Programs/Pesticides/
Registration/ SpecialRegistrations/.
VARIETY SELECTION
FUNGICIDE USE
