Author Archives: Maria Balota

Checking on Peanut Maturity in Virginia

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In only two weeks since my last peanut maturity advisory, peanut changed from this

'Bailey' peanut planted on May 5th, and dug on Sep 2nd.

‘Bailey’ peanut planted on May 5th, and dug on September 2nd.

to this

'Bailey' planted on May 6th and dug on September 17th.

‘Bailey’ planted on May 6th and dug on September 17th.

Based on the new picture taken on 9/17/14, it seems that 10 to 14 more days will be sufficient for early May planted peanut to reach maturity in Virginia. This seems to be in agreement with the heat units accumulated from May 1st, 2531 to 2672 °F, in southeastern VA and the number of days from planting (150 days) estimated to suffice for maturity of Bailey and Sugg.

However, peanut planted as late as May 15th seems to have reached similar maturity with the ones planted in the first week of May with far less heat units and days from planting. We conducted this morning a pod blasting in Southampton County, VA, for 27 fields planted from May 4th to May 15th. With the exception of three slower maturing fields, two of which from west Northampton County, NC, all other peanuts seemed to be ready to dig in 7 to 14 days from now. A few fields were ready to dig in the next few days, and actually the farmers growing these fields already started digging a couple days ago. A similar situation was reported by Extension Agent Janet Spencer who conducted a pod blasting in the Isle of Weight County, VA, on 9/17/14.

Have the new peanut cultivars reduced temperature requirements? Or the heat units we have had this year were “good” heat units including a higher frequency of “just right” peanut temperatures and “just right” precipitation amounts and distribution? Or maybe both? Regardless, digging decision is one of the most important decisions in peanut production and basing it on the pod mesocarp color, just like we are showing here, I highly recommend. Tomorrow, Sept 19, another pod blasting clinique will start at 9:00 AM at the Johnson Brothers buying station in Surry, VA. If interested, contact Extension Agent Glenn Slade, 757-294-5215.

Peanut Crop Update for Virginia

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Maturity wise, seasonal heat units accumulated by peanut fields from May 1st to Sep 1st in Virginia are between 2252 to 2376 °F. Therefore, we started a weekly pod maturity determination by the pod mesocarp color of Williams and Drexler (1981). We grouped the pods on a maturity board into white, yellow, orange, brown, and black color groups. The profile maturity classes defines white and yellow as immature, and orange, brown and black as mature pods; orange is defined as incipient maturity, brown full maturity, and black over mature pods. We used Bailey planted on May 5th and May 20th, and CHAMPS planted on May 27. Both Bailey and CHAMPS mature in approximately 145 days after planting or 2600 heat units. Peanut maturity determined on Sep 2nd

Our data indicate that in Virginia all plantings have the majority of the pods, 75 % to 91%, in the yellow and orange color groups (yellow predominates) with more spread for early May plantings (12% were in the white and 13% the brown group) and more uniform pods for late May planting (only 9% were a combination of white and brown).

Appearance wise, peanut vines start showing drought symptoms due to current high temperatures and absence of rainfall in many fields in Virginia. As of now, we are looking at 30 to 40 days to optimum maturity but more delay is expected if no significant rainfall will be soon received and in absence of irrigation.

Mysterious leaf spots in peanut

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In the past two weeks or so, there were discussions among specialists about peanuts showing a “mysterious leaf spot” of non-pathogenic origin (credit to pathologists Barbara Shew and Hillary Mehl); but the spot is similar in appearance to the early leaf spot when it starts and becomes irregular at later stages.

"Mysterious" leaf spot found in Suffolk, VA. At the initial stage, the spot looks like early leaf spot, but it has non-pathogenic origin.

“Mysterious” leaf spot found in Suffolk, VA. At the initial stage, the spot looks like early leaf spot, but it has non-pathogenic origin.

Dr. Jay Chapin with Clemson University thinks it is a physiological leaf spot; he calls it “irregular leaf spot”. He observed it to be more prevalent on runners, in particular GA09B, and resulting in yield reduction under certain circumstances. Dr. David Jordan calls it “peculiar leaf spot”. I also found it in research peanut fields in Suffolk and Southampton, VA; the spotting was under 25% of the total leaf area. To solve the “mystery” and get information on the frequency of this issue in NC, Dr. Jordan recently launched a survey and asked the Extension Agents to assess the presence and severity of the spot in approximately 20 fields in each county (4 to 5 areas in each field) using the table below. Because I also found the spot in several fields and I know of growers growing GA09B this year, I suggest we do the same in Virginia. Please use the table below; under “comments” please include information on the cultural practices used in each field, if possible, so we can better explain the cause of the spotting. This assessment can be used at winter meetings and presented at the APRES next year together with the NC Extension Agents.

Documentation of Leaf Spots in Peanut that is not early or late leaf spot or web blotch

Field ID (your designation) Spots present (yes/no) Severity (none, low = 25% or less leaflets with spots, moderate = 25 to 50% leaflets with spots, high = 50 to 75% leaflets with spots, very high = 75 to 100% leaflets with spots) relative to entire peanut canopy Comments
       
       
       

Late Season Weed Control in Peanut

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Yesterday a farmer asked what herbicide to use for ragweed control at this time of year. I am not a weed researcher so I asked the expert: Dr. David Jordan with the North Carolina State University. He recommended Cobra, but also cautioned with its use at this stage of development. Cobra cannot be applied within 75 days of harvest. This means that if the farmer sprays it now, he will have to postpone harvest until end of October. 2,4-DB (40 to 65 days pre-harvest interval) and Select (40 days pre-harvest interval) were also recommended for late season broad leaf weed control.

Ragweed mature plant.

Ragweed mature plant.

Dr. Hillary Mehl’s Peanut Cotton InfoNet (http://webipm.ento.vt.edu/cgi-bin/infonet1.cgi) service shows that peanut accumulated from May 1st and until mid-August across peanut growing region in Virginia from about 1840 heat units (at Waverley) to 1980 (at Skippers). The number of heat units accumulated only from August 1st to mid-August is about 200. Bailey and Sugg require about 2600 heat units to mature; this is approximately 690 more heat units needed to reach maturity. Assuming similar temperatures for the rest of August and September, the 690 heat units can be achieved by the first week of October, or the second week of October if September gets cooler, for a May 1st planted peanut. This means that some herbicides still can be used for weed control in peanut at this time, in particular for late planted peanut; but herbicide label needs to be carefully checked.

Determining the optimum harvest maturity is more complicated than checking the heat units and counting the number of days from planting, as you very well know. Therefore, I recommend that growers take advantage of the pod-blasting clinics that Extension Agents will organize in September. One will be on September 5th at Emporia. I will also send advisories with peanut maturity starting after the first week of September.

Peanut Leaf Injury from Mn and Provost

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Ten days ago we sprayed the second shot of manganese (Mn) mixed with Provost and Omega for disease control. We have heard that Provost can produce leaf burning if mixed with other products (with boron for example) but those incidents appeared to be unpredictable and inconsistent. This year, mixing Mn with Provost did affect us! The fields that were sprayed later in the day (the hottest part of the day) showed more severe burning than the ones sprayed in the morning. However in none of the fields the burning exceeded 5%; note, however, that the injured leaves were those at the top of the canopy with the best light capture and photosynthetic activity.

Peanuts were sprayed with a mixture of manganese, Provost, and Omega.

Peanuts were sprayed with a mixture of manganese, Provost, and Omega.

How do we know it was the mixture? Because in one field only half received Mn plus Provost plus Omega (leaf burning occurred) and half only received Provost and Omega (no leaf burning was observed). It could have been only Mn, however. Either way, I would caution farmers to double check labels and percentages of Mn before mixing with fungicides, Provost in particular. Also a good practice would be to apply chemicals, micronutrients in particular, early in the morning to avoid the heat.

Grain sorghum growth stage update

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Sorghum grows fast with good soil moisture and temperatures in July and August. Hybrids with maturity within 65 to 70 days from planting to flower and planted in late May to early July are blooming now. Get ready to spray Headline (8 oz/acre) for anthracnose control. Waiting with the fungicide until late flowering stage

Sorghum panicles at a late flowering stage. If over 50% of your field is at this stage, you should have sprayed Headline already.

Sorghum panicles at a late flowering stage. If over 50% of your field is at this stage, you should have sprayed Headline already.

may not be as effective as early flower applications.

Sorghum field at beginning flowering stage and when application of Headline for anthracnose control should be made.

Sorghum field at beginning flowering stage and when application of Headline for anthracnose control should be made.

Grain sorghum – crop update for Virginia

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Even though the first FSA crop acreage report for 2014 will be posted on August 15 (at http://www.fsa.usda.gov/FSA/webapp?area=newsroom&subject=landing&topic=foi-er-fri-cad), I know that several farmers in SE Virginia planted grain sorghum this year. For those and beyond,

Grain sorghum planted at Tidewater AREC on June 10, 2014

Grain sorghum planted at Tidewater AREC on June 10, 2014

here there are a couple updates to consider:

Depending on maturity, May planted hybrids are getting close to heading. Scouting for worms at this time and until hard dough is important. We recently found a relatively heavy corn earworm pressure in our “Official Variety Test” (OVT). Japanese beetle pressure also needs to be observed at this time as it may cause leaf damage for young plants. For both, Dr. Herbert recommended a mixture of Baythroid (2.8 oz) and Lannate (1.5 pt) in at least 15 gal of water for good penetration inside the whorls.

Double crop sorghum planted after wheat is probably no taller than 8 inches; still a good height for several herbicide options for broad leaf control. Grass and wheat volunteers can also be controlled but sorghum needs to be at least 15 inches tall. Details on herbicide options are at http://pubs.ext.vt.edu/AREC/AREC-29/AREC-29NP.html.

Sorghum is a crop and it should be treated as such. This includes knowledgeable soil sampling for pH and nutrient content, and treatment accordingly. Nutrient recommendations for sorghum can be found at http://www.soiltest.vt.edu/PDF/recommendation-guidebook.pdf.

My research group has been quite successful growing sorghum, full and double cropping, across SE Virginia. You can tour the 41 OVT hybrids we grow this year on September 11 during the Tidewater AREC Pre-harvest Field Tour. For details on this event ask Gail White at guwhite@exchange.vt.edu.

Has your peanut sufficient manganese?

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It appears that different peanut fields may have different needs for manganese fertilization this year. We made this observation while scouting several peanut fields last week: here at the Tidewater AREC and also in farmers’ fields in Southampton County. Even though we applied 1 qt of 9% liquid manganese almost three weeks ago, some fields appear to need more. If manganese deficiency symptoms occur, applying more manganese with the next fungicide treatment would be a good approach.

'Bailey' peanut showing manganese deficiency

‘Bailey’ peanut showing manganese deficiency

We have seen manganese deficiency late in the season in 2012. This year, rainfall was less than in 2012. However Bailey has excessive vine growth and precipitation was enough for most fields to exacerbate this characteristic.