Evaluation of foliar fungicides for control of leaf spot and soilborne diseases of peanut

摘要

Fungicides were evaluated for control of leaf spots, southern stem rot and other soilborne diseases of peanut. Soil type was Kenansville loamy fine sand with a history of Cylindrocladium black rot (CBR) and Sclerotinia blight, and a rotation of corn,cotton, peanut in 2012, 2011, and 2010, respectively. Plots were four, 35-ft rows spaced 36 in. apart with treatments applied to the two center rows. Treatments were arranged in a randomized complete block design with four replications separated by 10-ftalleys between blocks. Vapam 42% 7.5 gal/A was applied 8 in. deep with coulter and trailing chisel shank on 17 Apr for control of CBR. Peanuts were planted on 4 May with Admire Pro Systemic 550SC 9 fl oz/A delivered in furrow by microtube (5 gal/A) forthrips control. Foliar sprays were applied with three, D323 nozzles/row delivering 14.85 gal/A at a pressure 42 psi. Initial foliar sprays of Bravo Weather Stick + Folicur 3.6SC, Headline 2.09SC, Abound 2.08SC, Abound 2.08SC + Alto 0.83SL, Priaxor and Koverall 75DF + Topguard were applied at beginning pod (R3 15 Jul). Additional sprays including Fontelis 1.67SC, Bravo Weather Stik, Tilt/Bravo 4.3SE and Koverall 75DF + Bravo Weather Stik were applied thereafter according to the Va. Peanut Leaf Spot Advisory Program until beginning maturity (R_7, 5 Aug, 21 Aug, 9 Sep). A broadcast spray of Orthene 97S 8 oz/A on 30 May and 19 Jun was applied for further thrips control; Baythroid XL 2 fl oz/A + Steward EC 10 fl oz was applied on 21 Aug for insect control.Danitol 2.4EC 6 fl oz was applied on 16 Jul and 8 Aug for leaf hopper control. Standard practices were used for weed control and nutrient management throughout the season. Peanuts were dug from the center two rows of each plot 16 Oct and harvested 25 Oct. Yield was determined after drying and adjusting weight of whole pods to 7% moisture. Rainfall in May, Jul, Aug, Sep and Oct was 0.87, 2.55, 2.03, 3.00 and 2.11 in. below normal, respectively; rainfall in Jun was 2.94 in. above normal. Rainfall during the period totaled 20.04 in., which was 7.62 in. below normal. Average minimum air temperatures were 3°F above normal in Oct, normal (+-1°F) in May, Jun and Jul, 2°F below normal in Aug and 5°F below normal in Sep. Average maximum air temperatures were 2°F above normal in Jun, Jul and Oct, and normal (+-1°F) in May, Aug and Sep, according to records from a NOAA station 4 miles northwest of the test site. Normal represented the mean for the past 80 yrs of records.