In the Midwest and Eastern US, PLH are considered the most damaging insect pest to alfalfa yield and quality. PLH damage can lead to stunting, lower yields, reduced crude protein content, loss of forage palatability, and loss of stand density.
Here's some general information on PLH damage and management.
General Information
PLH control is generally needed during July and August in the Midwest and Eastern U.S.
Hot growing conditions can cause PLH populations to increase very quickly.
Pay special attention to new seedings and 3rd crop regrowth.
Threshold: 1 adult in 10 sweeps. Adults at threshold are an indication deadly immatures are not far behind. Immatures (nymphs) are the most damaging stage of PLH.
Do not spray stubble for PLH control; wait for 3-4 inches regrowth or about 5-6 days to entice PLH back into fields.
PLH can cause severe damage to alfalfa plants before the yellow “burn” appears on leaves; Use a sweep net to detect PLH before symptoms appear. Once symptoms appear, damage is already done.
Damage:
PLH causes a yellow V-shaped “hopper burn” pattern on leaves. Cell sap is extracted from plants, damaging the plant’s plumbing system (phloem and xylem), restricting water and nutrient flow.
“Hopper burn” is a result from the PLH injecting a toxin during nutrient extraction. Once the classic yellow Vshaped pattern appears, the damage is done. Purple coloration often occurs as plant sugars produced in leaves are unable to be processed normally.
Stunted plants will have reduced root growth, water usage and weeds can often gain advantage.
Reduces yield potential; yield losses up to 0.5 DM Ton/acre per cutting or more.
Reduces quality and crude protein, increases nondigestible NDF fiber levels resulting in reduced forage intakes and palatability.
Weakens alfalfa plant health allowing for other foliar diseases and stress to alfalfa.
New seedings are especially susceptible to PLH damage and can result in yield
CROPLAN Forage Specialist Jeff Jackson provides more information on potato leafhoppers in alfalfa in this video:
Contact your local Premier agronomist for more information on PLH management.
Every year, I get fooled by some article on milk pricing and the forecasters predicting the price that we will see in the future. They take on the nearly impossible quest of prediction with the same confidence of the newscaster reading the weather on my tv, and we all know how that went this spring. In February the mailbox price was in the $15 cwt range and now, fast forward to June, we are around $19 cwt. On a 600-cow dairy, that’s about $75,000 a month difference equating to just under a cool million in a year. How does your farm handle this volatility? I don’t think there’s a magic cookie cutter answer in how we manage this, and it appears volatility is here to stay in commodity prices.
Environmental conditions play a critical role in disease development. Watching the forecast and paying close attention to individual field conditions to help gauge the risk of disease development.
By the time you receive this newsletter, Independence Day will have gone by. I hope you enjoyed the day off. I should have done this in last month’s newsletter but let me give you some fireworks advice in case you have left over munitions. The most important thing to remember is after you light the fuse, Mr. Fireworks is no longer your friend. Then, while fleeing, don’t zig when you should have zagged. Now you know.
