Horticulture Update

By Noel Mues, Extension Educator, Furnas County

 

Preemergent herbicide applications – If the first application of preemergence herbicide for crabgrass control was applied prior to mid to late April; or if a turf area has a history of severe crabgrass infestation; a second application at this time will be beneficial in controlling crabgrass. This is true in all years, but especially important this year when we are recommending sequential applications on almost all turf areas given the extended season.

White grub preventive insecticides – On turfgrass with a history of white grub damage, the preventive insecticides imidacloprid (Merit) or halofenozide (Mach 2) are recommended to be applied by mid-July. With our above average early temperatures this year, the recommended application timing this year is slightly earlier. This year, these products are best applied from June 14 (Flag Day) to the 4th of July. Correct irrigation is important to effectiveness.  

Chinch bug damage has been fairly common in Buffalograss lawns. Chinch bugs injure grasses by withdrawing sap from plant tissues in the crown area. While feeding, they inject a salivary toxin that damages plant tissues and inhibits the translocation of water and nutrients. Initially, this feeding results in reddish-purple discoloration of the leaves. In turfgrass, damage appears as patchy areas which turn yellow and dry to a straw-brown color as feeding progresses. For information on detecting and controlling chinch bugs, see:

Chinch Bugs in Buffalograss and Zoysiagras Turf, University of Nebraska-Lincoln

Efficient lawn watering involves watering in the early morning when it is less windy and temperatures are cooler; watering at a rate that allows water to infiltrate the soil and not run off: and, moistening the soil to a depth of 4 to 6 inches at each watering cycle and then waiting until the turfgrass shows signs of needing water (footprints left in the grass, bluish-green cast) before irrigating again.

Watering Home Lawns, University of Nebraska-Lincoln.

Leaf scorch in trees appears as a uniform yellowing or browning of leaf edges. Browning may extend between the veins. Scorch indicates leaves are transpiring moisture faster than it is replaced by the roots. We have seen an increase in leaf scorch this year, most likely due to above average temperatures, dry, and windy conditions. Leaf scorch occurs for a variety of reasons.

• Young trees with large leaves (i.e. maples) and unestablished root systems, especially those growing on exposed, windy sites, often show leaf scorch.
• Young tender growth, especially lush growth promoted by nitrogen fertilizer, can scorch during hot, windy days even with established root systems.
• Leaf scorch may be a symptom of a root and/or trunk related problem.

Both over-and under-watering may lead to leaf scorch. When this symptom appears, avoid fertilization; check soil moisture for dryness or saturation; then use correct irrigation practices to encourage recovery.

Leaf Scorch, University of Nebraska-Lincoln

Hackberry decline/leaf drop – Hackberry trees often experience leaf drop in June. This may simply be due to an excessive amount of leaves set on. Hackberries are sensitive to herbicides and it may be a response to herbicide drift. If the trees continue to have a full leaf canopy, they should be fine. Over the last few years, a decline has also been noted in hackberries where trees experience excessive leaf drop, crown thinning, and some branch dieback. The cause is unknown but suspected to be related to a combination of stresses such as drought, herbicide drift, poor growing conditions, and other factors. When planting new trees, select for diversity.

Source: UNL Extension Horticulture, E-Hort News

 

Upcoming Activities

 

Performing Arts/Talent Contest – Piano, vocal, instrumental, dance - share your talent with others beginning at 7:00 p.m., Wednesday, June 27 at the Ella Missing Center, Arapahoe. Please pre-register by Monday, June 25.  

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The Holbrook Pre-Fair Beef, Lamb and Goat Show will be held on Saturday, June 30, 2012. Beef weigh-in begins at 6:30 a.m. and the show begins at 8:00 a.m. Lamb weigh-in begins at 9:00 a.m. and the show begins immediately after the beef show. Goat weigh-in begins at 11:00 a.m. and the show begins immediately after the lamb show.

 

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            The Furnas County Fair will take place the week of July 16-21, 2012. County fair premium books are available at the Extension Office or from the Bank in your local community.