Great Lakes Fruit, Vegetable & Farm Market EXPO Michigan Greenhouse Growers EXPO. December 4-6, DeVos Place Convention Center, Grand Rapids, MI

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1 Gret Lkes Fruit, Vegetble & Frm Mrket EXPO Michign Greenhouse Growers EXPO December 4-6, 2012 DeVos Plce Convention Center, Grnd Rpids, MI Crrot Where: Gllery Overlook (upper level) Room C MI Recertifiction credits: 2 (1B, COMM CORE, PRIV CORE) CCA Credits: NM(0.5) PM(1.5) Modertor: Ben Werling, Ocen Co. MSU Extension 2:00 pm Slow Relese Nitrogen: Will it work for crrot production in Michign? Dniel Brinrd, Horticulture Dept., MSU Corey Noyes, Horticulture Dept., MSU Kurt Steinke, Plnt, Soil nd Microbil Sciences Dept., MSU 2:30 pm Crrot Insect Updte Zsofi Szendrei, Entomology Dept., MSU 3:00 pm Crrot Vriety nd Disese Susceptibility Tril Mry Husbeck, Plnt, Soil nd Microbil Sciences Dept., MSU 3:30 pm Roles of Nemtodes in Crrot Production George Bird, Entomology Dept., MSU 3:50 pm Crrot Industry Development Progrm Updte John Bkker, Michign Asprgus Advisory Bord nd Michign Crrot Industry Development Progrm, DeWitt, MI 4:00 pm Session Ends

2 Aster Lefhopper Integrted Mngement in Crrots Zsofi Szendrei nd Adm M. Byrne Deprtment of Entomology, Michign Stte University, Est Lnsing, MI, Lb website: Aster lefhoppers re significnt insect pest of crrots, primrily becuse they trnsmit ster yellows phytoplsm. Disese symptoms vry from crop to crop, but ffected plnts typiclly hve distorted, discolored folige, tste bitter, nd re therefore unmrketble (Fig. 1). Figure 1. Crrot on the left showing signs of ster yellows nd helthy crrot on the right.

3 MANAGING THE ASTER YELLOWS - ASTER LEAFHOPPER COMPLEX A Insecticide tril results 1. The cornerstone of ster yellows mngement is the reduction of ster lefhopper pressure. 2. Insecticides re pplied bsed on thresholds, where vilble. Thresholds re determined bsed on the level of phytoplsm in the insects the higher the infectivity the lower the threshold. 3. Thresholds re crop species dependent, for exmple lettuce is more sensitive thn celery, nd celery is more sensitive thn crrots. So crrots typiclly hve the highest threshold out of these three crops. 4. The level of infectivity in the lefhoppers is mesured in chemicl rection in the MSU Plnt Dignostic Lb. The typicl turnround for smple from submission to results is 2-4 dys. Crop scouts nd extension personnel then use this to inform growers whether their fields re below or bove threshold. 5. Thresholds from the dignostic lb re given s follows: 4 lefhoppers / 100 sweeps. Insecticides re n integrl prt of ster lefhopper mngement, so it s importnt to evlute both registered nd experimentl compounds for their control. Becuse growers re often forced to mke mny pplictions during the growing seson, combintion of products my be needed. In 2012, we tested five different insecticides t the MSU Muck Soils Reserch Frm in Bth, MI. Products were pplied twice in the seson, on 24 July nd 15 August All compounds performed better thn the untreted plots (Fig. 2). Most of the chemicls did not differ from one nother, except for Asn, which significntly reduced ster lefhoppers compred to Admire Pro nd the high rte of Torc. As lefhopper numbers strted to increse two weeks fter the first ppliction, Admire Pro nd Actr were still performing well to suppress lefhopper numbers (Fig. 3). Figure 2. Averge number of ster lefhoppers per yellow sticky trp in field tril conducted t the MSU Muck Soils Reserch Frm. Products were pplied t the following rtes: Asn XL (9.6 fl oz/a), Actr (3 oz/a), Torc (low) (8 fl oz/a) + Induce (0.25% v/v), Admire Pro (1.2 fl oz/a), pyrifluquinzon (3.2 fl oz/a) + Induce (0.25% v/v), nd Torc (high) (16 fl oz/a) + Induce (0.25% v/v).

4 Figure 3. Number of ster lefhoppers per yellow sticky trp over time.

5 B. Interction of ster lefhoppers with non-crop plnts Both the ster lefhopper nd the ster yellows phytoplsm cn use mny plnt species s hosts. Cover crops, s well s the weeds, provide lterntive hosts for the lefhoppers nd source for picking up the ster yellows, therefore its importnt to understnd how the presence of these non-crrot plnts ffect lefhopper bundnce in the crrot crop. The effect of cover crop border tretments on ster lefhopper bundnce in crrots Ot, rye, brley, whet, nd triticle borders incresed the numbers of lefhoppers in the crrot plot reltive to the noborder tretment. Crrot plots with spelt borders hd the fewest lefhoppers on verge, nd this number ws significntly less when compred to brley, whet nd triticle border tretments. The presence of triticle lmost doubled the verge number of lefhoppers in the crrot plot reltive to the spelt. How do ster lefhoppers respond to different types of weeds? Aster lefhoppers were most bundnt in hnd weeded plots, which did not hve weeds. Plots tht were hnd weeded hd similr lefhopper bundnce s plots tht hd grssy weeds. Eliminting grsses but leving brodleved weeds in the plots significntly reduced the bundnce of lefhoppers in crrots, when compred to ll of the other tretments. SUMMARY: These findings tken together men tht cerel cover crops likely ttrct more lefhoppers to the field erly in the seson when the plnts re most sensitive to picking up the disese nd tht during the course of the seson brod-lef weeds re not likely to ttrct more lefhoppers to the field.

6 Crrot Vriety nd Disese Susceptibility Trils Dr. Mry K. Husbeck ( ) Michign Stte University, Deprtment of Plnt, Soil & Microbil Sciences, Est Lnsing, MI Cercospor nd Alternri lef nd petiole blights commonly occur every yer in Michign crrot fields nd require mngement to prevent crop loss. Cercospor blight is cused by the fungus, Cercospor crote, nd is n importnt folir disese of crrots. The fungus cn ttck young folige, either on the leves or petioles. Cercospor lef spot occurs s smll circulr brown spots which rpidly enlrge, ccompnied by yellow/red discolortion on younger leves nd girdled petioles, resulting in defolition. Alternri blight is cused by the fungus, Alternri duci, nd is usully detected lter in the seson on older folige. Symptoms of Alternri lef spot include drk brown/blck spots with yellow mrgins ppering on older leves. Petioles my lso become blighted. Severe disese results in wek petioles or defolition. Wrm tempertures nd long periods of lef wetness promote disese development. Spores of these fungi re wind-blown to nerby plnts or even djcent fields. Alternri nd Cercospor my occur together nd re mnged similrly. Methods to reduce disese pressure include plnting disese-free seed, following 2-yer crop rottion, minimizing overhed irrigtion during wrm wether, nd pplying fungicides. Methods to effectively schedule fungicide pplictions ccording to field scouting nd the TOM-CAST disese forecsting system hve been developed nd dopted by mny growers. Aster yellows is disese cused by phytoplsm trnsmitted by ster lefhoppers (Mcrosteles qudrilinetus) tht results in purplish leves nd root growth tht is distorted with fibrous, bittertsting root. Aster lefhoppers cquire the phytoplsm loclly from infected wild or cultivted crrots, or infective lefhoppers my be blown in on storm fronts coming from the southwest. Since ster lefhoppers cn remin infective for 100 dys, the disese is mnged by pplying insecticide sprys depending on lefhopper numbers, cultivr resistnce, nd the presumed proportion of infective insects. Tretment thresholds vry bsed on the infectivity rte of ster lefhoppers tht typiclly vries mong yers nd loctions. MSU Reserch conducted in 2012: Crrot Cultivr Tril. A totl of 18 cultivrs of crrots were obtined from Nunhems, Seminis, nd Bejo to be evluted in vriety tril tht ws plnted in commercil field. The tril ws rrnged in rndomized experiment using four replictes of ech cultivr. The tril ws plnted on 10 My with precision vcuum plnter t seed density of 200M per cre in 3-row beds. The beds were spced 5½ ft prt nd ech plot ws 50 ft long to get n ccurte plnting of ech replicte. Our reserch plot ws irrigted s needed bsed on the cooperting grower s schedule. The tril ws evluted for the totl number of plnts in 10 ft of row, number of ster yellows-infected plnts, number of plnts with fungl infections, nd totl yield on 10 October. Disese pressure from Alternri ws not evident until reltively lte in the growing seson due to the dry conditions tht previled for much of the summer. Some cultivrs hd very little Alternri nd included A85190, CR2289, nd 7315 (Figure 1). These cultivrs lso showed reduced mount of ster yellows. The cultivrs 5102 nd Snt Cruz hd significntly more Alternri thn mny of the other crrot cultivrs included in this study but Snt Cruz hd few plnts with ster yellows.

7 Disese (%) Sme-colored brs with letter in common re not significntly different b b A85190 (Nunehms) CR2289 (Seminis) 7315 (Seminis) 15 (Seminis) Yellowstone (Bejo) Diseses on Crrot Cultivrs d b Rngu (Seminis) Cupr (Bejo) Achieve (Seminis) PX (Seminis) Folir Alternri (%) Plnts with Aster Yellows (%) Bejo 2823 (Bejo) Finley (Bejo) 7318 (Seminis) Bilbo (Seminis) Cnd (Bejo) A85170 (Nunehms) 2384 (Seminis) 5102 (Seminis) Snt Cruz (Seminis) Figure 1. Aster yellow nd Alternri incidence on crrot cultivrs plnted in 2012, Mson County, MI. b Testing New Fungicide Products: A fungicide study ws conducted in commercil crrot field locted in Mson County, MI on sndy field tht ws previously plnted to sqush. The field ws cultivted, formed into beds, nd plnted to Cupr crrots with vcuum seeder on 20 April. Plots were rrnged in rndomized complete block design with four replictes. Ech tretment plot ws comprised of three-row bed (18 in. row spcing) 20 ft long with buffer of 5 ft between tretment plots within the row. The bed spcing ws 60 in. on center nd the seed popultion t plnting ws 200M/A. The overll plot dimension ws 16 beds wide by 100 ft long. Fungicide sprys were pplied with CO 2 bckpck spryer equipped with three XR8003nozzles spced 19 in. prt, operting t boom pressure of 50 psi, nd delivering 50 gl/a. Spry pplictions were pplied on 7-dy schedule for 13 weeks. Visul folir disese estimtes nd hrvest dt were tken on 2 October. Disesed petiole incidence nd infection severity were ssessed for ech crrot in the inner 5 ft of the center row. Petiole infection rtes were determined by counting the number of plnts with t lest one infected petiole. A petiole infection severity rting ws given to the crrot tops nd ws bsed on 1 to 5 scle (1= no lesions, 2=1-10 lesions per petiole, 3=11-20, 4=21-50, nd 5=>50 lesions per petiole) (dt not shown). Crrots were hndtopped nd weighed on pltform scle (dt not shown). The remining crrot folige in ech plot ws rted for percent lef blight. Dt were nlyzed using Sigm Stt version 3.1 (Systt Softwre Inc.) nd sttisticl differences were compred using the Fisher LSD multiple comprison test. As result of the hot nd dry wether conditions tht occurred during the 2012 growing seson, folir blight ws delyed in becoming estblished in the crrot plot. Becuse the disese developed lte in the seson, significnt differences mong the tretments were not detected (Figure 2). Follow up studies re need to determine whether the Alternri pthogen on crrots is sensitive to the strobilurin fungicides tht ply n importnt role in Michign grower s stndrd spry progrm. Acknowledgments. This mteril is bsed upon work supported by the Michign Crrot Committee, nd the MDA Specilty Crop Block Grnt for Crrot wrded to the Michign Crrot Committee. b-d -e b b-e b-e cd c-e d-e cd e

8 Endur 0.49 lb + Induce 1 pt Prixor 0.38 pt + Induce 1 pt Applied t 7-dy intervls Pristine 0.66 lb + Induce 1 pt Brvo WetherStik 2 pt Merivon 0.34 pt + Induce 1 pt Untreted control A. Products Alone Qudris 0.56 pt (pps 1-2,4-5,7-8), BWS 2 pt (pps 3,6,9) Endur 0.28 lb (pps 1-2,4-5,7-8), BWS 2 pt (pps 3,6,9) Omeg 1.5 pt (pps 1-2,4-5,7-8), BWS 2 pt (pps 3,6,9) Qudris TOP 0.75 pt (pps 1-2,4-5,7-8), BWS 2 pt (pps 3,6,9) Cbrio 20WG 0.75 lb -lt- BWS 2 pt Brvo WetherStik 2 pt Inspire XT 0.44 pt (pps 1-2,4-5,7-8), BWS 2 pt (pps 3,6,9) Untreted control B. Brvo Qudris 0.56 pt (pps 1-2,4-5,7-8), BWS 2 pt (pps 3,6,9) Qudris TOP 0.75 pt (pps 1-2,4-5,7-8), BWS 2 pt (pps 3,6,9) Untreted control C. Qudris Endur 0.28 lb + Induce 1 pt Endur 0.28 lb (pps 1-2,4-5,7-8), BWS 2 pt (pps 3,6,9) Endur 0.49 lb + Induce 1 pt Merivon 0.34 pt + Induce 1 pt + Endur 0.49 lb Merivon 0.34 pt + Induce 1 pt + Endur 0.28 lb Untreted control D. Endur Folir blight (%) Fig. 2. Comprison of fungicide progrms for the control of folir blights on crrot tht feture A, products pplied lone, B, Brvo Wether Stik (BWS), C, Qudris, nd D, Endur.

9 Role of Nemtodes in Crrot Production George W. Bird, Professor Michign Stte University Wht you know bout bd nemtodes in Michign crrot production: - There re three key nemtode pests of crrot in Michign 1. Northern Root-Knot Nemtode (occurs in muck nd minerl soils) 2. Crrot Cyst Nemtode (only occurs in muck soil in Michign) 3. Penetrns Root-Lesion Nemtode (highly ggressive in minerl soil) - All three types cuse low yields nd deformed crrots of poor qulity. - For field dignostics, look for res of poor plnt growth, pull plnts nd observe deformed tproots - Confirm dignosis through smples sent to MSU Dignostic Services. How to mnge the bd nemtodes in your crrot production system: - Northern Root-Knot Nemtodes nd Crrot Cyst Nemtodes cn be mnged through rottion with non-host crops such s corn, whet nd other smll grins. - Historiclly, fumignt nd non-fumignt (orgno-crbmte nd orgno-phosphte) nemticides hve been used in Michign crrot production. Tody, there re reltively few nemticides vilble for use in crrot production nd those tht re registered cn be difficult to obtin nd difficult to pply (see MSU Extension Bulletin 312 for product nd ppliction detils). - There re no crrot vrieties with resistnce to the bd nemtodes ssocited with Michign crrot production. - Anything tht cn be done to improve or mintin overll soil qulity will reduce risk to bd nemtodes. - A number of new nemticides re being mrketed for crrots. They hve not been widely evluted in Michign crrot production. There is nothing wrong with trying these on n experimentl bsis in strip trils. - Be sure to keep good records/field mps of nemtode problem sites for use in future decision mking. Wht you know bout the good nemtodes: - The soil-borne microbes et first. - You feed the bcteri. - The bcteri re food for the good nemtodes. - The good nemtodes feed your crrot plnts. - Be sure you know how this works (pge 70, MSU Ext. Bull. E-2983). How to mnge the good nemtodes in crrot production: - Anything you cn do to mintin or improve the helth of your soil with ssist the nemtodes in feeding your crrot plnts (see Cornell Univ. Soil Helth System).