influence of supplementary in-bed chloropicrin application on soilborne pest control in tomato...

ARTICLE IN PRESS

0261-2194/$ - se

doi:10.1016/j.cr

�Correspondfax: +1941 751

E-mail addr

(B.M. Santos).

Crop Protection 24 (2005) 779–784

www.elsevier.com/locate/cropro

Influence of supplementary in-bed chloropicrin application onsoilborne pest control in tomato (Lycopersicon esculentum)

James P. Gilreatha, Timothy N. Motisa, Bielinski M. Santosa,�, John M. Mirussob,Phyllis R. Gilreathc, Joseph W. Nolingd, John P. Jonesa

aGulf Coast Research and Education Center, University of Florida, 5007 60th Street East, Bradenton, FL 34203, USAbMirusso Fumigation Equipment, Delray Beach, FL 33483, USA

cFlorida Cooperative Extension Service, University of Florida, Palmetto, FL 34211, USAdCitrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA

Received 22 October 2004; received in revised form 10 December 2004; accepted 4 January 2005

Abstract

Four consecutive field trials were conducted in a four-season study to determine the long-term efficacy of supplementary in-bed

applications of chloropicrin (Pic) in addition to 1,3-dichloropropene plus Pic (1,3-D+Pic) on soilborne pest control and tomato

(Lycopersicon esculentum Mill.) yield. Treatments compared combinations of in-bed and broadcast 1,3-D and Pic with an untreated

control and were repeated over several seasons. Results indicated that in-bed applications of C-35 and MBr+Pic consistently had

the highest control of soilborne fungus (Fusarium oxysporum f.sp. lycopersici race 3), weeds (Cyperus spp.), and nematodes

(Meloidogyne spp., Belonolaimus spp., and Tylenchorhynchus spp.) and tomato fruit weights, followed by the C-35+Pic, and 1,3-

D+Pic, which had excellent performance in three of the four tomato seasons.

r 2005 Elsevier Ltd. All rights reserved.

Keywords: Methyl bromide; Fusarium oxysporum; Meloidogyne; Belonolaimus; Tylenchorhynchus; Cyperus

1. Introduction

Fungal pathogens, nematodes, and weeds are com-monly present in tomato (Lycopersicon esculentum Mill.)fields throughout the world. In the US, these pests haveto be effectively controlled to obtain satisfactory yield.Methyl bromide (MBr) has been used successfully as asoil fumigant with activity against a broad spectrum ofsoilborne pests since the early 1970s (Overman andMartin, 1978), but it is scheduled for a complete phase-out of production and use by 2005 (US EnvironmentalProtection Agency, 1999).

e front matter r 2005 Elsevier Ltd. All rights reserved.

opro.2005.01.002

ing author. Tel.: +1941 751 7636;

7639.

esses: [email protected], [email protected]

Research and grower demonstration trials haveshown that the combination of 1,3-dichloropropene+-chloropicrin (1,3-D+Pic) used with the herbicidepebulate typically results in pest control and crop yieldcomparable to that with MBr (Gilreath et al., 1994;Jones et al., 1995; Locascio et al., 1997). The primarypests controlled by 1,3-D and Pic are nematodes andsoilborne diseases, respectively. The herbicide contri-butes to control Cyperus rotundus L. and Cyperus

esculentus L.Most data related to the performance of 1,3-D+Pic

were generated with in-bed applications. A few yearsago, it was recognized that the onerous label restrictionsrequiring field-workers at the time of application towear the maximum in personal protective equipmentcould be mitigated by broadcast-applying 1,3-D+Pic.Success with any method of fumigant applicationdepends on obtaining a sufficient concentration of

www.elsevier.com/locate/cropro

ARTICLE IN PRESSJ.P. Gilreath et al. / Crop Protection 24 (2005) 779–784780

fumigant for a long enough period to eliminate thetargeted organism (Minuto et al., 1999; Wang et al.,1999). Fumigant volatilization from the soil can limitefficacy by reducing the concentration of the fumigant inthe soil and/or shortening the exposure duration.The retention of soil fumigants is influenced by soil

moisture and temperature, which change rapidly inresponse to climatic changes within the upper 5 cm offield soil. As soil temperature increases or moisturedecreases, soil fumigants move more rapidly (Gamlielet al., 1998; Gan et al., 1998; Wang et al., 1998).Although no odour is perceived at the time of broadcastapplication of 1,3-D+Pic, rapid volatilization of fumi-gant is likely once it reaches the upper few centimeters ofthe soil profile.The placement of the fumigant in relation to the

location of pests within the soil profile influences itsretention and efficacy. Nematodes are known to move inthe soil in response to moisture and other factorsrequired for life (Gouge et al., 2000). Deep placement of1,3-D+Pic during broadcast application is likely toprovide control of nematodes because they are generallydeeper in the soil profile at the beginning of the season.Furthermore, 1,3-D does not volatilize as readily as Pic.In contrast, soilborne disease propagules are welldistributed in the soil profile and planting beds are notformed until seven or more days after 1,3-D+Picbroadcast application, during which time there is nopolyethylene mulch to prevent Pic volatilization, result-ing in ineffective control. Therefore, an additional in-bed application of Pic may improve soilborne diseasecontrol.Recognizing that the potential exists for loss of

efficacy as a result of gaseous losses of Pic duringbroadcast applications of 1,3-D+Pic, a four-seasonstudy was conducted to determine the long-term efficacyof supplementary in-bed applications of Pic in additionto 1,3-D+Pic on soilborne pest control and tomatoyield.

2. Materials and methods

The experiment was conducted in four consecutivetomato seasons from fall 2000 to spring 2002 at the GulfCoast Research and Education Center in Bradenton,Fla. on a EauGallie fine sand. Treatments consisted of(a) untreated control, (b) in-bed MBr+Pic (67:33 v/v) ata dose of 392L/ha, (c) in-bed 1,3-D+Pic (C-35) at327L/ha, (d) broadcast C-35 at 243L/ha, (e) broadcastC-35 at 243L/ha followed by in-bed Pic at 154 kg/ha,and (f) broadcast 1,3-D at 168L/ha followed by in-bedPic at 154 kg/ha. Treatments were assigned in 12.2-mlong, single-bed plots arranged in a randomizedcomplete block design and replicated 5 times. The71-cm-wide, 20-cm-tall raised beds were spaced 3m

apart on centers. Treated beds were separated by non-treated beds to maintain treatment integrity over time.This study was conducted on the same site each seasonto allow for evaluation of pest development asinfluenced by the fumigant treatments. Physical refer-ence points were established to allow relocation of eachplot in the same spot over the duration of the study, thusassuring continued monitoring of treatment effects overmore than one season. The test area was chosen becauseof a past history of Fusarium wilt (Fusarium oxysporum f.sp. lycopersici race 3).Subsurface irrigation and overhead sprinklers were

used to provide sufficient moisture for initial landpreparation and construction of beds. Starter fertilizer(45N-19P–17Kkg/ha) was broadcast prior to treatmentapplication. C-35 and 1,3-D were broadcast with aYetter Avenger coulter applicator (Yetter Farm Equip-ment, Colchester, Illinois, USA) with knives spaced30 cm apart delivering fumigant at a depth of 31 cm innon-bedded soil. Within seven days of broadcastapplications of 1,3-D and C-35, the herbicides pebulateand napropamide (4.5 and 2.2 kg ai/ha, respectively)were applied broadcast and soil-incorporated 15 cmdeep in all plots. Beds were formed 7 to 13 days afterherbicide application, at which time the in-bed fumi-gants (C-35, Pic, and MBr+Pic) were injected 25 cmbelow the top of the finished bed using chisels spaced31 cm apart.Immediately after bed formation, a single (fall 2000,

spring 2001, fall 2001) or two (spring 2002) micro-irrigation tubes (T-Systems International, San Diego,California, USA; 0.029L/s, 31 cm emitter spacing) wereplaced 10 cm from the bed center and buried 5 cm deep.Beds were covered with low-density polyethylene filmmulch (0.03mm thick) and 6-week-old tomato seedlingswere transplanted on single rows with 0.60m plantspacing. Tomato (‘Florida 47’) plants received waterand fertilizer (1–2.8 kgN/ha; 0.9–2.2 kgK/ha) dailythrough the micro irrigation system. Foliar pesticideswere applied following local grower practices.Tomato plant vigour at about 6 weeks after trans-

planting was evaluated visually on a percentage ratingscale by comparing all plots to the most vigorous plotwithin the test. Cyperus densities were determined eachseason at approximately 1 month prior to crop harvesttime by counting the number of plants emerged on thebed top. Tomato fruits were harvested twice each seasonby separating non-marketable from marketable fruit,sorting and weighing marketable fruits by size-gradeaccording to current market standards. Fusarium wiltincidences and nematode soil samples were taken withineach plot at the time of the second harvest. The diseaseincidence values were expressed as percentages of thenumber of living tomato plants present. Soil samples fornematode assay were collected with a probe (2.5 cm wideby 20 cm deep) from the rhizosphere of 8–10 tomato

ARTICLE IN PRESSJ.P. Gilreath et al. / Crop Protection 24 (2005) 779–784 781

plants per plot, and the nematodes were separated from100 cm3 soil using a standard sieving and centrifugationprocedure (Jenkins, 1964).Data were subjected to ANOVA using SAS (SAS

Institute, 2000). To minimize variability and maximizethe power to detect differences between treatments,nutsedge and nematode data were transformed via log10(observation+1) prior to ANOVA. Likewise, Fusarium

incidence data was normalized with arc sin transforma-tion prior to ANOVA. Preplanned treatment compar-isons were obtained with single degree-of-freedomorthogonal contrasts.

Table 1

Incidence of Fusarium wilt (Fusarium oxysporum f.sp. lycopersici race 3) in

Treatmentb Dose per ha Application method Fall 2000 (

MBr+Pic 392L In-bed 0

C-35 327L In-bed 0

C-35 243L Broadcast 0

C-35+Pic 243L+154kg Broadcast+in-bed 0

1,3-D+Pic 168L+154kg Broadcast+in-bed 5

Control 0 — 48

Single degree-of-freedom orthogonal contrasts

Control vs. MBr+Pic *

Control vs. C-35 in-bed *

Control vs. C-35 broadcast *

Control vs. C-35+Pic *

Control vs. 1,3-D+Pic *

MBr+Pic vs. C-35 in-bed NS

MBr+Pic vs. C-35 broadcast NS

MBr+Pic vs. C-35+Pic NS

MBr+Pic vs. 1,3-D+Pic NS

aFusarium oxysporum incidence transformed with arc sin before ANOVA.bAbbreviations: MBr ¼ methyl bromide; Pic ¼ chloropicrin; 1,3-D ¼ 1

(P40:05); * ¼ significant effect ðPp0:05Þ:

Table 2

Cyperus spp. density in tomato fields as influenced by fumigant treatmentsa

Treatmentb Dose per ha Application method Spring 2001


C-35 327L In-bed o1




Control 0 — 51




Control vs. C-35 broadcast NS




MBr+Pic vs. C-35 broadcast *



aCyperus densities transformed with log+1 before ANOVA. Data obtainbAbbreviations: MBr ¼ methyl bromide; Pic ¼ chloropicrin; 1,3-D ¼ 1

ðP40:05Þ; * ¼ significant effect ðPp0:05Þ:

3. Results and discussion

There were significant season by treatment interac-tions for Fusarium wilt incidence, Cyperus densities,Meloidogyne, Belonolaimus, and Tylenchorhynchus po-pulations, and marketable tomato fruit yield. Therefore,data from each season will be discussed separately. ForFusarium wilt incidence, the infection level depended onthe time of the year that the trials were performed, withsimilar responses during the two fall seasons and in thetwo spring seasons (Table 1). In fall 2000 and 2001, onlythe untreated control plots were severely affected by the

tomato fields as influenced by fumigant treatmentsa

%) Spring 2001 (%) Fall 2001 (%) Spring 2002 (%)

11 0 25

11 3 20

20 13 44

12 1 18

6 1 16

19 68 35

* * *

* * *

NS * NS

* * *

* * *

NS NS NS

* NS *

NS NS NS

NS NS NS

Data obtained between 11 and 14 weeks after treatment.

,3-dichloropropene; C-35 ¼ 1,3-D+Pic; NS ¼ non-significant effect

(plants/m2) Fall 2001 (plants/m2) Spring 2002 (plants/m2)

o1 3

1 3

11 70

3 43

2 60

16 51

* *

* *

NS NS

* NS

* NS

NS NS

* *

NS *

NS *

ed 4 weeks after treatment.


ARTIC

LEIN

PRES

S

Table 3

Meloidogyne spp., Belonolaimus spp., and Tylenchorhynchus spp. populations in tomato fields as influenced by fumigant treatmentsa

Treatmentb Dose per ha Application

method

Meloidogyne spp. Belonolaimus spp. Tylenchorhynchus spp.

Fall 2000

(Number/

100mL soil)

Fall 2001

(Number/

100mL soil)

Spring 2002

(Number/

100mL soil)

Fall 2000

(Number/

100mL soil)

Fall 2001

(Number/

100mL soil)

Spring 2002

(Number/

100mL soil)

Spring 2001

(Number/

100mL soil)

Fall 2001

(Number/

100mL soil)

Spring 2002

(Number/

100mL soil)

MBr+Pic 392L In-bed 2 0 4 0 0 0 0 2 1

C-35 327L In-bed 0 0 25 0 0 0 0 1 1

C-35 243L Broadcast 15 8 154 25 0 12 20 10 7

C-35+Pic 243L+154kg Broadcast+

in-bed

3 0 21 3 0 1 0 3 2

1,3-D+Pic 168L+154kg Broadcast+

in-bed

10 1 32 23 0 15 7 3 6

Control 0 — 12 48 315 18 24 31 28 21 16


Control vs. MBr+Pic * * * * * * * * *

Control vs. C-35 in-bed * * NS * * * * * *

Control vs. C-35 broadcast NS NS NS NS * * NS NS NS

Control vs. C-35+Pic * * NS * * * * * *

Control vs. 1,3-D+Pic NS * NS NS * NS NS * NS

MBr+Pic vs. C-35 in-bed NS NS NS NS NS NS NS NS NS

MBr+Pic vs. C-35 broadcast * NS * * NS * * * NS

MBr+Pic vs. C-35+Pic NS NS NS NS NS NS NS NS NS

MBr+Pic vs. 1,3-D+Pic NS NS NS * NS * NS NS NS

aNematode populations transformed with log+1 before ANOVA. Data obtained between 12 and 14 weeks after treatment.bAbbreviations: MBr ¼ methyl bromide; Pic ¼ chloropicrin; 1,3-D ¼ 1,3-dichloropropene; C-35 ¼ 1,3-D+Pic; NS ¼ non-significant effect ðP40:05Þ; * ¼ significant effect ðPp0:05Þ:

J.P

.G

ilreath

eta

l./

Cro

pP

rotectio

n2

4(

20

05

)7

79

–7

84

782

ARTICLE IN PRESSJ.P. Gilreath et al. / Crop Protection 24 (2005) 779–784 783

disease, with 48 and 68% of the tomato plants affectedby the disease during each season. All fumigant treat-ments presented low Fusarium wilt infestation (p13%).In the spring 2001 and 2002 seasons, only the broadcastC-35 treatment (20 and 44% incidences, respectively) didnot differ from the control (19 and 35% incidences,respectively). At the same time, the broadcast applicationof C-35 had higher percentage of tomato plants affectedby Fusarium wilt than any other of the fumigants. Therest of the fumigants provided the same levels of diseasecontrol within each of the spring seasons.Fumigants significantly influenced Cyperus densities

during three of the four conducted trials. In fall 2000,there was not enough weed pressure. However, duringthe following three seasons, there was a differentialeffect of the fumigants on Cyperus densities (Table 2). Inspring and fall 2001, broadcast C-35 was the onlyfumigant that failed to improve weed control, resultingon 73 and 11 Cyperus plants/m2 at 4 weeks aftertreatment. The other fumigants were as effective asMBr+Pic, with densities p3 Cyperus plants/m2. Incontrast, during the spring 2002 tomato season, only thein-bed application of C-35 was as effective as MBr+Pic,whereas the rest of the fumigants were equal to theuntreated control.In terms of nematode control, only the populations of

three genera (Meloidogyne, Belonolaimus, and Tylench-

orhynchus) were affected by the fumigants when samplednear tomato harvest time. Meloidogyne juvenile popula-tions were affected by the fumigants only during fall2000, fall 2001, and fall 2002 (Table 3). During the threegrowing seasons, the broadcast application of C-35failed to improve Meloidogyne control with respect tothe untreated control. The same situation occurred with

Table 4

Marketable tomato fruit yield as influenced by fumigant treatmentsa

Treatmentb Dose per ha Application method Fall 2000 (t/ha


C-35 327L In-bed 52




Control 0 — 26




Control vs. C-35 broadcast *




MBr+Pic vs. C-35 broadcast NS



aData obtained from two harvests at 12 and 14 weeks after treatment.bAbbreviations: MBr ¼ methyl bromide; Pic ¼ chloropicrin; 1,3-D ¼ 1

ðP40:05Þ; * ¼ significant effect ðPp0:05Þ:

1,3-D+Pic in the fall 2000 and spring 2001 seasons.When comparing fumigants to MBr+Pic, there were nodifferences in Meloidogyne control between this treat-ment and the in-bed application of C-35, C-35+Pic, and1,3-D+Pic.Fumigant treatments only affected Belonolaimus

populations during the same tomato seasons as forMeloidogyne (Table 3). All the fumigants improvedBelonolaimus control with respect to the untreated, withthe exception of broadcast-applied C-35 in fall 2000, and1,3-D+Pic in fall 2000 and spring 2002. In fall 2000, thein-bed-applied C-35 and C-35+Pic treatments werecomparable with the performance of MBr+Pic. Thesame situation repeated during fall 2001 and spring2002. In the latter growing season, broadcast C-35 and1,3-D+Pic were also as effective controlling Belonolai-

mus as MB+Pic.There were significant fumigant effects on Tylench-

orhynchus populations in the spring and fall 2001, andspring 2002 growing seasons, in which the broadcast-applied C-35 failed to control the nematode (Table 3). Incontrast, in-bed-applied C-35, C-35+Pic, and 1,3-D+Pic consistently provided the same Tylenchor-

hynchus control levels as MBr+Pic. The Fusarium wilt,weed, and nematode data revealed that the only twotreatments that were consistently comparable to thecommercially applied MBr+Pic in controlling all threenematode genera throughout the planting seasons werethe in-bed application of C-35 and the broadcastapplication of C-35 followed by in-bed injection of Pic.Marketable tomato fruit yield were affected by the

application of the fumigants in each of the croppingseasons (Table 4). In fall 2000 and fall 2001, all thefumigant plots produced significantly higher yields that

) Spring 2001 (t/ha) Fall 2001 (t/ha) Spring 2002 (t/ha)

49 60 65

44 60 62

35 59 34

47 57 42

48 64 32

5 34 22

* * *

* * *

* * NS

* * *

* * NS

NS NS NS

* NS *

NS NS *

NS NS *


ARTICLE IN PRESSJ.P. Gilreath et al. / Crop Protection 24 (2005) 779–784784

the untreated control, representing increments of ap-proximately of 2.4 and 1.8 times in average marketabletomato fruit weight. During those cropping seasons,there were no yield differences between MBr+Pic andeither of the tested fumigants. In spring 2001, allfumigants caused sharp marketable yield increases.When comparing against MBr+Pic, all the fumigantsperformed similarly as this commercial standard, withthe exception of the broadcast-applied C-35, whichproduced approximately 29% less marketable tomatofruit weight than MBr+Pic. The following year, only thein-bed-applied C-35 was comparable to MBr+Pic. Theyield data showed that in-bed applications of C-35 andMBr+Pic consistently produced the highest fruitweights in the four cropping seasons, followed by theC-35+Pic, and 1,3-D+Pic, which had excellent perfor-mance in three of the four tomato seasons.Results suggested that the value of additional Pic,

with broadcast C-35 or 1,3-D is the greatest when pestpressure is high. The data indicated that broadcast C-35may provide pest control similar to that with in-bed C-35 when used repeatedly over multiple tomato croppingseasons. The comparable performance of in-bed C-35was consistent with previous research (Gilreath et al.,1994; Jones et al., 1995; Locascio et al., 1997).

Acknowledgements

Published as Florida Agricultural Experiment StationJournal Series No. R-10597.

References

Gamliel, A., Grinstein, A., Beniches, M., Katan, J., Fritsch,

J., Ducom, P., 1998. Permeability of plastic films to methyl

bromide: a comparative laboratory study. Pesticide Sci. 53,

141–148.

Gan, J., Yates, S.R., Wang, D., Ernst, F.F., 1998. Effect of

application methods on 1,3-dichloropropene volatilization

from soil under controlled conditions. J. Environ. Qual. 27,

423–438.

Gilreath, J.P., Jones, J.P., Overman, A.J., 1994. Soil-borne pest control

in mulched tomato with alternatives to methyl bromide. Proc. Fla.

State Hortic. Soc. 107, 156–159.

Gouge, D.H., Smith, K.A., Lee, L.L., Henneberry, T.J., 2000.

Effect of soil depth and moisture on the vertical distribution of

Steinernema riobrave (Nematoda: Steinernematidae). J. Nematol.

32, 223–228.

Jenkins, W.R., 1964. A rapid centrifugal-flotation tech-

nique for separating nematodes from soil. Plant Dis. Rep. 48,

692.

Jones, J.P., Gilreath, J.P., Overman, A.J., Noling, J.W., 1995. Control

of soil-borne diseases of mulched tomato by fumigation. Proc. Fla.

State Hortic. Soc. 108, 201–203.

Locascio, S.J., Gilreath, J.P., Dickson, D.W., Kucharek, T.A.,

Jones, J.P., Noling, J.W., 1997. Fumigant alternatives to methyl

bromide for polyethylene-mulched tomato. HortScience 32,

1208–1211.

Minuto, A., Gilardi, G., Gullino, M.L., Garibaldi, A., 1999. Reduced

dosages of methyl bromide applied under gas-impermeable plastic

films for controlling soilborne pathogens of vegetable crops. Crop

Prot. 18, 365–371.

Overman, A.J., Martin, F.G., 1978. A survey of soil and crop

management practices in the Florida tomato industry. Proc.

Fla. State Hortic. Soc. 91, 294–297.

SAS Institute, 2000. Proprietary Software Release 8.1. SAS Institute,

Cary, North Carolina, USA 3884p.

US Environmental Protection Agency, 1999. Protection of strato-

spheric ozone: incorporation of Montreal protocol adjustment for

a 1999 interim reduction in class I, group VI controlled substances.

Federal Register 64, 29240–29245.

Wang, D., Yates, S.R., Jury, W.A., 1998. Temperature effect on

methyl bromide volatilization: permeability of plastic cover films.

J. Environ. Qual. 27, 821–827.

Wang, D., Yates, S.R., Wang, D., 1999. Spatial and temporal

distributions of 1,3-dichloropropene in soil under drip and shank

application and implications for pest control efficacy using

concentration-time index. Pesticide Sci. 55, 154–160.

influence of supplementary in-bed chloropicrin application on soilborne pest control in tomato...

Documents