REPORT TO THE AGRICULTURAL RESEARCH FOUNDATION FOR THE OREGON PROCESSED VEGETABLE COMMISSION December 2011

Transcription

1 REPORT TO THE AGRICULTURAL RESEARCH FOUNDATION FOR THE OREGON PROCESSED VEGETABLE COMMISSION December 211 Project Title: Ascospore Trpping of Sclerotini sclerotiorum in Snp Ben Fields nd Root Rot Mngement Principl Investigtor: Cynthi M. Ocmb, Ext. Specilist & Associte Professor Botny nd Plnt Pthology, OSU - Corvllis Telephone: (541) ocmbc@science.oregonstte.edu Coopertors: Nthn Miller, Postdoctorl Reserch Assistnt, BPP, OSU Dvid H. Gent, USDA-ARS, Corvllis Robert B. McReynolds, North Willmette Reserch & Ext. Center, OSU Jim Myers, Dept. of Horticulture, OSU Bckground nd Justifiction: A polymerse chin rection (PCR) ssy specific to S. sclerotiorum hs been developed by Gent et l. nd ws successfully used during 28 nd 29 to detect scospores of S. sclerotiorum on glss rods (Rotorod spore trp) in experimentl ben plntings locted on the OSU-BPP frm. Knowing whether spores re present or bsent during the growing seson llows for the development of predictive model for scospore production nd relese s well s periods of high infection risk. Successful prediction of periods with high or low infection risks would enble better timing of protective fungicides. If the bsence of the scospores could be predicted within snp ben field, then 1-spry fungicide progrm could be utilized with greter confidence nd lower risk of ctstrophic losses. Root rot cused by Fusrium solni nd severl other soilborne pthogens cn reduce ben yields when conditions re fvorble for disese, especilly when bens re rotted too frequently in the sme ground. Amending soil nd/or seed with biocontrol microbes my help reduce yield losses cused by root rot. Ben cultivrs with the persistent color (pc) genes hve mny desirble trits for processing but cn hve difficulty with stnd estblishment. Beneficil microorgnisms my help protect seedlings nd improve stnd estblishment of these sty-green lines. Just prior to 2, few fungicides were registered for white mold control in snp ben: Roniln, Benlte, Topsin, Rovrl s well s the ineffective Botrn. Since tht time, Benlte nd Roniln use in ben hs been withdrwn by the EPA while Endur (bosclid), Switch 62.5WG (fludioxonil plus cyprodinil), nd Omeg 5F (fluzinm) hve been registered for white mold control in snp ben. Tnk mixtures of thiophntemethyl (Topsin M 7WP, Topsin 4.5FL, nd T-Methyl 4.5F AG) nd iprodione (Rovrl 4F, Nevdo 4F) controls mold problems in snp ben. Spry trils tht we conducted during 24 through 27 evluted vrious rtes of Topsin/Rovrl tnk mixes s 1- or 2-spry progrm in ddition to exmining unregistered s well s mterils subsequently registered for ben mold control. It hs been severl yers since the commission hs supported ben mold spry trils nd during tht time we conducted limited studies with privte compny support. With the support of the Oregon Processing Vegetble commission, we conducted tril for comprison of fungicides currently registered for white mold of snp ben when used lone in 1- nd 2-spry progrm, llowing comprison of product efficcy.

2 Objectives for 211 nd Accomplishments: 1. Evlute scospore detection of S. sclerotiorum using multiple Rotorod spore trps nd monitor environmentl conditions within snp ben fields for model development of scospore bsence events. Ascospores of the white mold pthogen were detected in 35 out 98 smples so there were number of dtes when no spores were detected. The first ben plnting hd very little disese by commercil hrvest wheres the second field hd firly high disese pressure but still no scospores were detected. Replicte smples will be processed during the winter to conform or correct scospore detection dtes. The snp ben cultivr 91G ws plnted in Chehlis silt lom soil t the OSU Botny Field Lbortory, Corvllis, OR. Field #1 ws plnted on June 16 th nd Field #2 ws plnted on Jul 29 th using 18-in. row spcing nd pproximtely 26, seeds/a. Fertilizer (4 lb/a of ) ws bnded t plnting followed by 1 lb/a of bnded t the second to third trifoliolte lef stge. For weed control, Eptm 7E (4.5 pt/a) nd Trefln 4L (2 pt/a) were brodcst nd incorported 4 dys before plnting; Rptor (4 oz/a) + Bsgrn (16 oz/a) were pplied t the second trifolite stge. The field ws sprinkler-irrigted weekly s needed with 1 to 1.5 in. of wter. Rotorod spore trps were moved mong fields in order to monitor scospores presence prior to 1% bloom through the following 3 weeks in ech field. Rods were replced every 48 hours, nd subsequently tested for the presence of scospores using polymerse chin rection (PCR) specific for Sclerotini. Up to four Rotorod spore trps were in the fields t one time but usully there were fewer, due to trps being moved between fields s well s the mechnicl filure of trps. Environmentl dt ws collected from HOBO U3 Dt logger (Onset, Cpe Cod Mss). Air temperture, reltive humidity nd lef wetness were monitored within the cnopy. Soil temperture ws monitored t 1 nd 3 inch depths, nd soil moisture ws monitored t the 3 inch depth. This equipment ws moved between fields to obtin dt during crucil white mold development times. Ascospores were detected in 35 out 98 Rotorod smples. Unlike in previous sesons, the positive results don t pper to be concentrted during the flowering period. In the first plnting, there were seven dys during the flowering period with no scospores detected (Fig.1) nd this plnting ended up with very little disese t hrvest s one of the rre 211 het spells occurred during flowering in the first plnting nd overll tempertures were wrmer during flowering in this plnting. In the second plnting, there were two dys without scospore detection during flowering (Fig. 2). After the 2nd plnting ws hrvested, none of the Rotorod smples tested positive. In previous sesons most lte seson smples were positive. It is uncler why this seson s detection results ppered inconsistent with the pttern seen in previous sesons. The bckup rotorod smples will be processed to confirm findings.

3 .4 Soil Moisture (m 3 /m 3 ) Lef Wetness (%) Reltive Humidity (%) Temperture (F) Air 1" Soil 3" Soil 1% bloom Hrvest 7/6/11 7/13/11 7/2/11 7/27/11 8/3/11 8/1/11 8/17/11 8/24/11 Dte Figure 1. Environmentl dt nd Sclerotini sclerotiorum detection dt in the 1st snp ben plnting. Drker circles with plus indicte positive PCR detection of S. sclerotiorum nd lighter circles indicte negtive test result in the PCR test.

4 .4 Soil Moisture (m 3 /m 3 ) Lef Wetness (%) Reltive Humidity (%) Temperture (F) % bloom Hrvest Air 1" Soil 3" Soil 8/31/11 9/7/11 9/14/11 9/21/11 9/28/11 1/5/11 1/12/11 Dte Figure 2. Environmentl dt nd Sclerotini sclerotiorum detection in the 2 nd snp ben plnting. Drker circles with plus indicte positive PCR detection of S. sclerotiorum nd lighter circles indicte negtive test result in the PCR test.

5 Objective 2 for 211 nd Accomplishments: Evlute biofungicide effects on snp ben stnd estblishment, root rot severity, nd subsequent pod yields. Biocontrol pplictions ppered to suppress growth of snp ben cultivr, Sprtcus. Nontreted plnts hd the highest numericl yield, followed by Qudris Flowble ppliction. Shoot weight ws gretest in Qudris followed by the nontreted plnts. On the edge of Field #1 nd Field #2 outlined in Objective 1, three plntings were mde using rndomized block strip design. Field study 1 nd 2 were plnted on July 29 th nd Aug 23 rd, respectively, with seed of Sprtcus ( sty-green vriety) tht hd been treted with UV-C light for 1 hr. Sprtcus plots were treted with soil drench t plnting with mterils listed in Tble 1, or plots were left untreted. A tnk mix of Rovrl 4F (2 pints/a) nd Topsin 4.5FL (3 fl oz/a) ws pplied to plots t 1% bloom for white nd gry mold control. Root weight, root volume, nd pod yield were determined t pproximtely 21 dys fter 1 % bloom commenced. Ten plnts were dug by hnd from ech plot nd soil ws gently removed by hnd. Plnts were bgged up, returned to the lb, nd refrigerted until weighed. Ech shoot ws shered from its respective root system t the soil line nd ll pods were hrvested by hnd for rw weight determintion. Tble 1. Mterils evluted for Fusrium root rot control on snp ben during 211 Tretment # Mteril ctive ingredient Rte 1 RootShield WP Trichoderm hrzinum(krl-ag2) 32 oz/a 2 MicroAF experimentl microbil mix 12.8 fl oz/a 3 Serende Soil Bcillus subtilis (QST 713 strin) 2.2 fl oz/1 ft 4 Serende Soil 4.4 fl oz/1 ft 5 Qudris Flowble zoxystrobin: Rhizoctoni root rot of.6 fl oz/1 ft Streptomycetes lydicus (WYEC 18) 6 Actino-Iron plus iron 15 lb/a 7 nontreted The Sprtcus stnd ws uneven in Field study #2 nd this plnting ws plnted too lte for full pod mturity by 21 dys fter 1% bloom. A floting row cover ws used to protect plnts from killing frost bout 12 dys before hrvest in this lst plnting. So the dt re presented seprtely by field. Plnts in both fields hd severe root decy, probbly becuse of nightly 3-minute irrigtion events pplied fter 1% bloom to ensure white mold pressure for Objectives 1 & 3. But root development differed mong the tretments in both studies nd is reflected in root weights. Generlly there ws no improvement in root weights with ny biocontrol pplictions (see Figure 3), reflecting greter degree of vribility in root nd shoot weights thn the smpling ccounted for this yer. In field study 1, it ppers tht the biocontrol pplictions reduced ben yields in terms of both pods nd vegettive shoot growth. Qudris Flowble ppliction to soil, lbeled for Rhizoctoni control in snp ben, ws ssocited with incresed pod yield nd shoot weights compred to most of the biocontrol tretments, but Qudris ws not significntly different from the nontreted control plnts.

6 Rw shoot weight (grms) Rw pod weights (grms) Pod yield per plnt -- Study 1 b bc cd cd d d Averge shoot weight -- Study 1 c bc c c c b Rw shoot weight (grms) Rw pod weights (grms) Pod yield per plnt -- Study 2 b b b b b b Averge shoot weight -- Study 2 b b b b b b Rw root weight (grms) 5 Averge root weight -- Study 1 b bc 4 bcd d cd bcd Rw root weight (grms) Averge root weight -- Study 2 b b b b b b RootShield WP (32 oz/a) MicroAF soil (12.8 fl oz/a) Serende Soil (2.2 fl oz/1 ft) Serende Soil (4.4 fl oz/1 ft) Qudris (.6 fl oz/1 ft) Actino-Iron (.6 fl oz/1 ft) nontreted RootShield WP (32 oz/a) MicroAF soil (12.8 fl oz/a) Serende Soil (2.2 fl oz/1 ft) Serende Soil (4.4 fl oz/1 ft) Qudris (.6 fl oz/1 ft) Actino-Iron (.6 fl oz/1 ft) nontreted Figure 3. Effect of biocontrol pplictions on root, shoot, nd pod weights of the snp ben cultivr, Sprtcus. Within ech grph, brs lbeled with the sme letters re not significntly different (P=.5) s determined by Fisher s LSD test.

7 Objective 3 for 211 nd Accomplishments: Compre the efficcy of fungicides registered for white mold in snp ben. Four-row plots (5 by 15 ft), rrnged in rndomized complete block design with three to four replictions, were estblished within ech of the two 91G ben fields outlined in Objective 1. Tretments with currently-registered fungicides s 2-spry progrm were pplied t 1% bloom nd repeted week lter while the single-ppliction tretments were pplied t 1% bloom. Sprys were pplied with CO 2 bckpck spryer clibrted to deliver 22 gl of wter/a t 38-4 psi using three 82 flt fn nozzles on 19 in. spcings. On the 21 st dy fter the initil fungicide ppliction ws mde t 1% bloom, the plnts were hrvested. The number of pods, presence of white or gry mold on pods > 2 inches in length nd number of stems with white or gry mold were determined for 3 individul plnts selected rbitrrily from the center two rows of ech plot. Disese levels were lmost nonexistent in plnting 1 (dt not shown) wheres in plnting 2, reltively modertely high levels of white mold were found (Tble 2) but virtully no gry mold ws detected (dt not shown). White mold levels verged 6.6 mrketble pods per plnt in the nontreted control plots. The percentge of pods > 2-in. in length nd number of stems ffected by white mold ws lower in most of the fungicide tretments when compred to the nontreted plnts. However, tretment with JMS Stylet-oil lone or tnk-mixed with Kumulus fforded no improvements compred to the nontreted plots. A 2-spry progrm of Omeg ws inferior to 2-spry progrms tht included Rovrl, Topsin, Endur, nd Switch. White mold severity generlly incresed when single ppliction of ny fungicide is compred to its respective counterprt in 2-spry progrm, but mens were not significntly different. Phytotoxicity ws not observed with ny tretments. Tble 2. Tretments pplied t 1 & 1 % bloom to snp ben '91G' Fungicide Tretment (rte/cre) z Appliction number % pods with white mold y Avg. stem # with white mold y nontreted (wter JMS Stylet-Oil (1 gl) b Kumulus DF (7 lb) + JMS Stylet Oil (.5 gl) b Rovrl 4F (2 pt) + Topsin 4.5FL (3 fl oz) 2.7 de.1 fg Topsin 4.5FL (3 fl oz) 2. e.6 g Endur (8 oz) + JMS Stylet Oil (.5 gl) 2.2 de.3 g Rovrl 4F (2 pt) cde.55 de Switch 62.5WG (11 oz) cde.6 g Omeg (13.6 oz) b.66 cd Rovrl 4F (2 pt) + Topsin 4.5FL (3 fl oz) cd.52 de Topsin 4.5FL (3 fl oz) 1.8 de.17 fg Endur (8 oz) + JMS Stylet Oil (.5 gl) cde.41 def Rovrl 4F (2 pt) cde.27 efg Switch 62.5WG (11 oz) 1.9 de.32 defg Omeg (13.6 oz) bc.93 c Z 1% nd 1% bloom pplictions were mde on 12 Sep nd 19 Sep 211, respectively. y Mens re bsed on the % pods or stem number ffected per plnt. Numbers within the sme column followed by the sme letters re not significntly different t P=.5 s determined by Fisher s protected LSD test.