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ISSUE 12  July 23, 1998

 

TREES

Pine Moths

    Often referred to as Zimmerman moths, Dioryctria sp. moths can cause serious damage to pine trees throughout North Dakota. The larvae tunnel between the bark and wood on trunks and large branches of Ponderosa, Scotch and Austrian pines. Most damage reported in North Dakota has been on Ponderosa pines. Although pines of almost any age may be infested by these moths, those from 5 to 15 feet tall are often damaged most. Younger trees tend not to be as heavily infested, while older trees are more tolerant of the insects.

    There are three possible species present in North Dakota. In areas where the moth larvae have been identified to species, D. tumicolella has been confirmed. We currently do not have data regarding spray timing for the insect in North Dakota. Work is underway to determine when sprays will be most effective in northeastern and southwestern North Dakota. A trap will be monitored near Walhalla to determine when spraying should take place there, while pupation will be observed near Hettinger to help determine future spray recommendations for that area.

X-Disease

    X-disease is a serious problem of chokecherry in North Dakota. This disease causes discolored and deformed foliage and fruit, stunted leaves and shoots, gradual decline and ultimately death of infected native and planted chokecherry and some other Prunus species across the state.

   The phytoplasma that causes X-disease is transmitted by leafhoppers that feed on leaves. Symptoms may begin to develop in late June of the year following transmission of the phytoplasma, but might not develop for several years, depending on vigor and disease resistance of the infected plant. On plants exhibiting symptoms, leaves will become greenish-yellow in early summer and may develop reddened margins. During July and August, the foliage turns red or orange. Rosettes of leaves may develop at shoot tips due to shortened internodes caused by the disease. Fruit yield is often reduced. Berries are undersized and may be pointed and red rather than the dark purple typically seen in chokecherries. Leaves and berries with and without symptoms may be found on the same plant. Highly susceptible or stressed chokecherry plants may die two or three years after X-disease symptoms develop. Where there are several plants, about half of them would be expected to die within eight years of symptom development.

    There are currently no reasonable control measures for X-disease. Selection of good sites (fertile, drained soil with a regular moisture supply), avoidance of herbicide damage, and extra care (irrigation during drought, fertilizer when needed) and other actions that result in good plant vigor will result in longer-lived plants. Interplanting of chokecherry with other shrubs or trees may reduce the spread of the disease and would reduce the impact if plants are lost. Drs. Jim Walla and Zong Ming Cheng of NDSU have identified chokecherry plants that appear to be highly resistant to X-disease in the Plant Materials Center experimental plots at Bismarck. Those plants are being developed for release to the public.

Marcus Jackson
Extension Forester

 

SPECIALITY CROPS - WHEN TO SWATH AND COMBINE

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.

Yellow Field Pea

Swath when peas and pea vines are yellow colored. Thresh when seeds are firm and can no longer be penetrated with thumbnail. 20% moisture content or lower. Some shatter loss usually occurs. Mixing wet soil with peas can cause staining - a discount grading factor.

Green Pea

Swath when peas are mature and have a good green color. Pea vines are yellow colored. If desiccating, apply when vein pattern of uppermost pods is easily recognized and 75% to 90% of the pods have turned to yellow tan. Seeds are firm, but no longer penetrable with a thumbnail. Pea vines may or may not be prostrate depending on variety and conditions. 2% bleached peas is maximum. Bleached seeds are caused by high humidity, bright sunshine and warm temperatures.

Feed Pea

Swath when pea vines are yellow colored. Vines are often prostrate. Seeds are firm, but no longer penetrable with a thumbnail. Combine settings and operation are not as critical for feed peas as to human food peas. Admixtures of various pea kinds are allowed. Some bleached peas, split, cracked or split peas, and earth tagged peas are accepted for feed peas.

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 (White)-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 or 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.

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. Shatters easily if not cut on time.

Buckwheat

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.

Canaryseed

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.

Fababean

Swath when 25% of the plants in the field have the lower-most pods turning from green to black. Thresh when bean can no longer be dented with thumbnail-20% moisture content or lower. Overdry seed will readily shatter. Fababean plants turn black as they ripen. Because of the high moisture content of the plant, a fairly light swath should be laid to hasten dry-down.

Canola

Swath when overall moisture content of seeds on plants average 30-35%. About 30-40% of the seeds in pods on main stem will have color change. Most color changes will be on the bottom third of the plant. Allow to cure and ripen from 10 to 14 days in swath before combining. Another sign of canola near swathing is the natural yellowing and leaf drop. When canola is primarily stems, branches and pods, its probably near the swathing stage. Use swath roller to prevent wind movement of swaths.


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