Author Archives: Sean Malone

Sugarcane aphids found in sorghum field in Suffolk, Virginia

Dr. Ames Herbert confirmed the presence of sugarcane aphids, Melanaphis sacchari, in a sorghum field at the Tidewater Agricultural Research and Extension Center in Suffolk, Virginia, on Sep. 17, 2015. Sugarcane aphid spreads as winged adults on wind and storm fronts so infestations can spread rapidly—so to be on the safe side, sorghum fields should be scouted.

There are several other aphid species that can infest sorghum but sugarcane aphid can be differentiated from the others being smooth, cream yellow, with two, short dark cornicles (“tailpipes”) on the hind end.

Research by Mike Brewer, Texes AgriLife, and David Kerns, LSU, has provided the most up-to-date Econominc Injury Level (EIL) of 50 to 125 aphids per leaf at sorghum prices of $4/bu; and the currently recommended Economic Threshold (when the insecticide needs to be applied to prevent the population from reaching the EIL) of 25 – 30% infested plants with 50 aphids per leaf.

After heading, according to work in other states, one of the more effective insecticide products is Sivanto (Bayer CropScience). Please refer to the Section 2(ee) Recommendation for the lower (but effective) rate of Sivanto @ 4-7 oz/A here: http://www.cdms.net/ldat/ldC4K023.pdf (please take note of the pre-harvest intervals and other directions found in the Section 2(ee)).

BMSB and kudzu bug soybean scouting report update for Sep. 16, 2015

Scouts Ed Seymore and Jamie Hogue have found multiple soybean fields in Virginia this week (early to mid-September) with threshold levels of brown marmorated stink bug (BMSB)–please refer to the figure for locations and numbers, noting that the columns for BMSB nymphs and BMSB adults need to be added together for calculating threshold numbers (more on that below).  Of course this is just a small sample of the fields out there, but their reports stress the need to scout your fields, especially those fields at the late R4 growth stage (full pod, where pods are 3/4-inch [2-cm] long at one of the four uppermost nodes) and at R5 (beginning seed, where seed is 1/8-inch [3-mm] long in the pod at one of the four uppermost nodes on the main stem).

Due to their concentrations along field edges, BMSB should be sampled using 2-minute visual counts, 15-sweeps with a net, or beat cloth (wide rows only), by walking 10-20 feet into a field, taking several samples in different parts of the field edge, and determining the average.  The thresholds for BMSB (adults + medium and large nymphs) in soybean, where BMSB is the predominant species, is 3-5 in a 2-minute visual count; 3-5 per 15 sweeps; or 0.5 per row foot using a beat cloth.  If a threshold is met, an edge-only insecticide treatment with a labeled pyrethroid, carbamate, or organophosphate at the R5 soybean growth stage can provide high levels of control.  As always, please be sure to read and follow the label.

Note that if your sampling finds a mix of stink bug species (e.g., BMSB, green, and brown) throughout the field, use thresholds of 5 per 15 sweeps or 1 per row foot (total all species, adults and nymphs).

KB_BMSB_16_Sep_2015Kudzu bug numbers are generally low.

BMSB and kudzu bug distribution maps for the week ending August 27, 2015

Brown marmorated stink bug and kudzu bug were found in soybean in several additional Virginia counties this week–please refer to the distribution maps below.  Fields at or above the BMSB threshold of 3 to 5 total adults + medium and large nymphs in a 2-minute visual count were found in the following counties:  Bedford (12 BMSB per sample), Shenandoah (8 BMSB), Nelson (4 BMSB) and Henry (3 BMSB).   Thanks to our scouts Ed Seymore and Jamie Hogue, and to ANR Agent Scott Reiter for their reports this week.  BMSB_map_27_Aug_2015KB_map_26_Aug_2015