NDSU Crop and Pest Report

Plant Science


ISSUE 15  August 14, 2003

HARVESTING FIELD PEAS

Most new cultivars of peas are straight (direct) combined. Peas are only swathed to preserve quality if there is uneven crop maturity or heavy weed pressure present. If green_-otyledon pea harvest is delayed, bleaching may occur. Bleaching is caused by rainfall at maturity, high humidity, bright sunshine and warm temperatures. If green peas are swathed, timely harvest is essential, for green pea will be more susceptible to bleaching in the swath than if left standing.

When swathing peas, the seed needs to be at physiological maturity. At this stage of growth, the majority of pods should have turned from green to a yellow color. The crop matures from the bottom pods upward. Swathing will normally result in increased harvest losses, but swather modifications make the procedure easier and will reduce harvest loss. Vine-lifters enable producers to get under the pea vines and lift them over the cutting knife. Many growers use a pickup reel as well. Peas should be swathed in the early morning or late afternoon when the pods are tough to reduce shattering losses. Combining should not be delayed after swathing, because pea swaths are susceptible to movement by wind.

Many short to medium-vine and semi-leafless pea cultivars have characteristics that allow straight harvesting compared to cultivars with indeterminate and prostrate-vine growth. For example, semi-leafless pea have a more open canopy, remain erect longer and dry down more rapidly after a rain or heavy dew than indeterminate long-vine type.

The first choice for direct harvest of short to medium-vine and semi-leafless pea varieties is a combine header with a floating cutter bar or flex head. Also, attachments such as lifter guards and pickup reels reduce losses and improve harvest efficiency. Direct harvesting of weak and prostrate-vine cultivars is most efficient with an aggressive pickup attachment and a lead coulter on a standard combine.

Field peas should be combined with seed moisture of 14 to 20 percent. At this moisture range, the seeds are firm and no longer penetrable with a thumbnail. Harvest should occur during humid conditions to minimize seed shatter.

Correct combine settings and operation are important to maintain seed quality. Reel speed should be slow to minimize seed shatter. Low cylinder speeds, normally 350 to 600 rpm, should be used to minimize seed cracking or splitting. Initial concave settings of 0.6 inch clearance at the front and 0.2 inch at the rear are suggested. Adjust combine settings as crop and weather conditions change.

 

SPECIALTY CROPS-WHEN TO SWATH AND COMBINE

Hot weather in recent days has tended to push many crops to mature at an increased rate. Questions on when to swath and harvest certain alternative crops are being asked. Below are some comments and suggestions:

Crop

Other Information

Lentil

Swath when lowermost pods are tan colored and rattle when shaken. Thresh when seeds test 18% moisture content or lower. Overdry lentils (8-10%) are hard and difficult to process or consume. Plants may still be green when pods are ripe. Crop typically matures in patches. Some shatter loss usually occurs. Watch out for swaths being scattered by the wind.

Millet, Proso

Swath when seeds in the upper one-half of the panicle have matured. Seeds in lower portion will be in dough stage but will have less color. Harvest millet when its below 13% moisture. Proso shatters easily if not cut on time.

Mustard

Swath when seed moisture content is 25%. Seeds are firm when pressed between fingers. Oriental - 75% yellow seeds. Brown - 60% reddish brown seeds. Yellow - 100% yellow seeds. Straight combine yellow mustard whenever possible. Watch for cracked seeds. Moisture content of seed should be 13% or lower. Swaths are fluffy and subject to wind damage. Lay swaths in direction of prevailing winds. Immature green seed will not change in color in the swath. Use swath roller.

Safflower

Crop has finished blooming. Seeds heads are tan to brown in color. Leaves and heads are spiny with little green evident. Crop should be straight combined if evenly matured. Mature seed is striped or white and rubs freely from the heads.

Buck-wheat

75% of the seed coats have turned brown. Flowering is nearly complete. Difficult to penetrate seed with thumbnail. Seeds continue to fill in the windrow or after light frost for about 3 days. Bottom seeds will likely be lost due to shattering. Cut immediately after a killing frost.

Canary-seed

Straw is bleached, hulls are shiny and golden colored. Seeds are reddish-brown. Delay cutting canaryseed until it is fully mature. Canary seed will not thresh cleanly until the heads are dry. Canaryseed is resistant to shattering and weathering. Dehulled seed is severely discounted.

Duane R. Berglund
NDSU Extension Agronomist
duane.berglund@ndsu.nodak.edu

 

ERGOT IN SMALL GRAIN

During the last week of July I participated in the Spring Wheat Quality Council tour. The tour visited a total of just over 300 wheat fields in most counties of the state. A number of wheat fields that I visited had a relatively high incidence of ergot and the only rye field that we visited was loaded with it. Other groups on the tour also reported finding ergot and there was general concern about the level of ergot incidence in the state this year. Someone raised the questions, why is there so much ergot this year and is there varietal resistance to it?

There is an excellent NDSU extension publication by Marcia McMullen and Charles Stoltenow on ergot that can be found on the Internet at:

http://www.ext.nodak.edu/extpubs/plantsci/crops/pp551w.htm

Please refer to this publication if you are interested in the full details of what ergot is, the damage it causes to both plant yield and animal health if used as feed and how it is controlled. Direct yield losses due to ergot are usually small. However, if wheat contains more than 0.05% by weight of the ergot sclerotia (black fungal bodies), it is graded as ergoty and could be discounted or rejected for use in food related channels.

What does ergot look like?

Ergot appears as a dark purple or more often a black fungal mass that replaces kernels in the small grain head. Generally only a few kernels in a head are affected, but as the fungal body is usually larger than normal kernels and extends beyond the tip of the glumes of the kernels they replace, one can spot ergot when walking through a ripening field. In harvested grain, ergot bodies appear as black chalky kernels (see attached photo). These ergot bodies, if returned to the soil will be the source of inoculum for future infestations. They germinate in the summer and produce spores that can be carried by the wind. Spores that are able to enter the floret during flowering can develop into ergot bodies. Cool wet weather during flowering favors the development of ergot is cereals. Perhaps the wet and cool weather that prevailed during flowering in many parts of the state predisposed this year’s crop to ergot.

Is there varietal resistance to ergot?

There has been no recent screening of HRSW varieties for resistance to ergot in ND. This week I visually evaluated varieties for presence of ergot in two variety trials that were planted in farmers’ fields in Ransom and Richland counties. When considering the data from both locations, all varieties had some ergot; no variety was completely resistant. Granite was consistently the most affected. Hanna, Reeder and Parshall generally had less ergoty grains than the other varieties. Please note that these results are from only two sites and for one year and should not be used to definitively characterize the level of resistance in HRSW varieties. They do, however, indicate that varietal difference may exist. The differences between the susceptibility of varieties to ergot that were noted could be related to the openness of the florets of the varieties (more open florets should enable greater infection) or to the timing of their flowering relative o the presence of inoculum.

Ergot Control

Ergot is best controlled through rotations. Small grains should be rotate with non-susceptible crops (including forage grasses) for at least one year.

Joel Ransom
NDSU Extension Agronomist - Cereal Crops
joel.ransom@ndsu.nodak.edu


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