Peanuts – Yellow in the Canopy

July 8, 2021

More rain coming in and out of the week ahead. Hurricane Elsa is estimated to approach near SC in about 5 days, with some bands possibly earlier. Making use of opportunities as we have them to maintain fungicide coverage will help all the more to put our disease management in a more secure position. Playing ketchup is only fun in the tomato processing business.
Different yellows are showing up in the canopy around this time of year, including more yellow flowers of pods to come. Tomato spotted wilt seems to be becoming visible more readily this season, which can leave plants partly yellow and stunted with mottled leaves, concentric rings, and streaks.
Yellow “V” shaped lesions near the tips of leaves are feeding injury from the potato leafhopper. These hoppers usually show up first around field edges. Our treatment threshold is 15-20% of leaves symptomatic, but if we see it showing up in force early we can always treat the field edges rather than waiting for the whole field to become symptomatic. Just depends on how much time there is. If we are just seeing the start of it, rains ahead may remove the hoppers for us. The feeding injury, however, will still be visible for several days and may take more than a week to dissipate, which is one reason to make sure the hoppers are still present if we are considering an insecticide spray. Most insecticides labeled for leafhopper are fairly broad spectrum (orthene, pyrethroids, besiege).
Manganese deficiency is another yellow symptom that characteristically first appears in the tops of leaves and appears as yellow chlorosis between the veins of the leaf. N deficiency can be visible in the whole plant and tends to most severely affect the oldest leaves at the bottom; N deficiency does not have as strong a vein pattern and can lead to stems that are thinner and elongated, and over time growth will be stunted. Between the two, if there looks to be a good amount of nodules and they are pink/red inside (active) and more of the yellow leaves are near the top, chances are it is Mn deficiency.
image of hopperburn image of Mn def image of surfactant and lls lesions image of aspergillus crown rot