Page 1
ROOT-KNOT NEMATODE MANAGEMENT IN ZIMBABWE :
CURRENT AND FUTURE TRENDS
48th TOBACCO WORKERS CONFERENCE, SOUTH CAROLINA
P.T. Makunde, T.S. Mahere, C. Chinheya and S. Dimbi
Tobacco Research Board, Zimbabwe
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 2
NEMATODE CONTROL IN ZIMBABWEHas mostly relied on the use of the fumigants eg•Methyl-bromide in
the seedbeds and
• 1.3 D and EDB in the field.
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 3
ADVANTAGES OF FUMIGANT NEMATICIDES
• Good return on investment
• have a broad-spectrum of activity,
• very effective when correctly applied
• Long period of control
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 4
INTRODUCTION
• In line with international trends the fumigants – no longer acceptable for use on tobacco.
• What options are available for nematode control?
SOME AGROCHEMICALS NO LONGER RECOMMENDED FOR USE ON TOBACCO IN ZIMBABWE
ACTIVE INGREDIENT CATEGORY1,3-Dichrolopropene/Methyl bromide NematicideAcephate, Thiodicarb InsecticidesAlachlor, Trifluralin HerbicideAldicarb Nematicide/InsecticideBenomyl FungicideDimethenamid, Metolachlor, HerbicidesEthylene dibromide NematicideFenvalerate InsecticideMethamidophos, Monocrotophos Insecticides
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 5
ALTERNATIVE SYNTHETIC NEMATICIDES
TRB working on
• Chemical alternatives (seedbed and field)
• Genetic resistance
• Cultural control K RK71
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 6
SOME WORK ON THE CHEMICAL ALTERNATIVES
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 7
MATERIALS AND METHODS
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 8
Evaluation of Agrochemicals – Seedbed
• 1m2 beds • 3 blocks
• 2 varieties used
• 0.5 m x 0.45 m area pulled out for assessment
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 9
Evaluation of Agrochemicals - Field
• A susceptible variety & a resistant var• Trials conducted over three seasons
• 3 rows/plot• 32 plants/row• 5 treatments• 3 blocks
32
THE TREATMENTS1. an untreated control,
2. a standard,
3. The test product at the lab determined rate,
4. a lower
5. a higher rate
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 10
NEMATODE POPULATION EVALUATION• Soil samples collected
from around the base of the plants
• Taken to the greenhouse
• Susceptible tomato plants planted
• Galling on the tomato plants indicates nematode populations
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 11
GALLING ON TOMATO PLANTS
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 12
ROOT GALLING ASSESSMENTS
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 13
SCORE DEGREE OF GALLING0 Free from galls 1 < 5 galls2 Trace to 25 galls3 20 – 100 galls4 Numerous galls, mostly discrete5 Numerous galls, many coalesced6 Heavy, mostly coalesced7 Very heavy, mass invasion, slight root growth8 Mass invasion, no root development
Daulton and Nasbaum (1961) scale of 0 – 8ROOT GALLING ASSESSMENTS
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 14
Alternative NematicidesThe following were evaluated;
• Metham sodium• Metham potassium• Methyl iodide• Fluopyram• Fluensulfone (MCW-2)
methyl isothiocyanategenerators
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 15
1. METHAM SODIUM
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 16
• Beds watered - activate weeds & nematodes.
• MeNa applied as a drench
• Covered - polythene sheets for 7 days.
2.
METHAM SODIUM - SEEDBEDS
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 17
METHAM SODIUM - APPLICATION
•Soil aerated - a fine tilth with a spade.
•Sowing - 28 days after product application.
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 18
THE RESULTS
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 19
0
200
400
600
800
1000
Grass Weeds Broadleaf weeds
No o
f wee
ds p
er m
2
Weed Type
ControlMeBrMeNa - 50 mlMeNa- 100 mlMeNa - 150 ml
Weed populations in MeNa treated plots
a
a
b b b b b b b b
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 20
ROOT GALLING ON TOBACCO SEEDLINGS
012345678
Control Methylbromide
MeNa50ml
MeNa100ml
MeNa150ml
Gall
ratin
g (S
cale
0 -
8)a
b
aa a
•Root galling low
•All three rates effective
MeBr MeNa Cont
The observation: Seedlings in MeBr, MeNa and untreated plots
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 21
METHAM SODIUM FIELD EVALUATION
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 22
Metham Sodium – Field Application • A liquid formulation
• Applied using fumigation guns or tractor tines
• Fumigation conducted 14 days before planting
MANUAL APPLICATIONTractor Application
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 23
0
1
2
3
4
5
6
Gal
l rat
ing
(sca
le 0
-8)
Treatment
a
b
c
b b b
RKN susceptible Variety RKN resistant Variety
Performance of Metham sodium in the field
ab
a aaa
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 24
SUMMARY – METHAM SODIUM USE•Broad spectrum activity in seedbeds -controls nematodes and weeds
•Registered at the rate of 100 ml in 4 L water/m2
•In the field - applied at the rate of 4 ml/planting station
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 25
CHALLENGES WITH METHAM SODIUM USE IN THE FIELD
• Can give inconsistent performance if not properly applied.
• Reported to be corrosive to equipment
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 26
2. METHAM POTASSIUM &3. METHAM IODIDE
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 27
APPLICATION METHOD
• MeK – same as Metham sodium
• Methyl Iodide -applied under 125 gauge polythene sheets.
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 28
2. RESULTS – METHAM POTASSIUM
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 29
0
50
100
150
200
250
300
Broadleaf grasses
No.
of w
eeds
per
m2
area
Weed type
Untreated controlMe-BrMe-Na (std)Me-K 80 ml/m2Me-K 100 ml/m2Me-K 120 ml/m2
Weed populations in Me-K treated plots
a
b b b b b
a
b b b b b
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 30
00.5
11.5
22.5
33.5
4
Cont Me-Br Me-K80
ml/m2
Me-K100
ml/m2
Me-K120
ml/m2
Cont Me-Br Me-K80
ml/m2
Me-K100
ml/m2
Me-K120
ml/m2
K M10 K RK66
ROOT-KNOT NEMATODE ON SEEDLINGS
a
b
c dd a b b b b
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 31
3. RESULTS - METHYL IODIDE
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 32
WEED COUNTS - METHYL IODIDE
0
50
100
150
200
250
300
350
Broadleaf Grassses
No.
of w
eeds
per
m2
area
Weed type
Untreated control
Methyl Bromide
Methyl iodide 10 g/m2
Methyl iodide 20 g/m2
Methyl iodide 30 g/m2a
c cb c
c cb
c
a
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 33
RKN GALL RATINGS ON SEEDLINGS FROM METHYL IODIDE TREATED PLOTS AT PULLING
0
1
2
3
Untreatedcontrol
Methylbromide
Methyliodide 10
g/m2
Methyliodide 20
g/m2
Methyliodide 30
g/m2
a
b b b b
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 34
4. FLUOPYRAM
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 35
0
0.5
1
1.5
2
Root
gal
ling
(sca
le 0
-8)
Treatment
Fluopyram Applied at sowing
0
0.5
1
1.5
2
Root
gal
ling
(sca
le 0
-8)
Treatment
Fluopyram Applied 7 days after sowing
RKN GALL RATINGS AFTER FLUOPYRAM APPLICATION
a aaa
b
a aaab
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 36
00.5
11.5
22.5
33.5
4
Root
gal
ling
(sca
le 0
-8)
Treatment
Fluopyram Applied at sowing
00.5
11.5
22.5
33.5
4
Root
gal
ling
(sca
le 0
-8)
Treatment
Fluopyram Applied 7 days after sowing
RKN GALL RATINGS AFTER FLUOPYRAM APPLICATION
a aaa
b
a
bb
a
b
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 37
FLUOPYRAM – FIELD TRIALS
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 38
0
1
2
3
4
5
6
7
3 WAP 8 WAP 13 WAP
Gal
l rat
ing
(0 –
8)
Untreated control Metham-sodium stdFenamiphos std Velum 500SCVelum 400SC (0.05 ml/ p.s.) Velum Split application
Galling of tomato plants from soil assayed in the greenhouse
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 39
Root galling in Fluopyram treated plots - 1
00.5
11.5
22.5
33.5
44.5
5
Root
-kno
t gal
ling
(Sca
le 0
-8)
KM10 (S) K RK72 (R)
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 40
012345678
Con
trol
Fena
(STD
)
Fluo
(0.3
L/h
a)
Fluo
(0.6
L/h
a)
Fluo
(0.9
L/h
a)
Fluo
(1.2
L/h
a)
Con
trol
Fena
(STD
)
Fluo
(0.3
L/h
a)
Fluo
(0.6
L/h
a)
Fluo
(0.9
L/h
a)
Fluo
(1.2
L/h
a)
K M10 K RK64
Root
-kno
t gal
ling
(0 -
8)
Root galling in Fluopyram treated plots - 2
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 41
• Effective for rkn control both in the seedbed and field
• Only registered for field use @ 0.9 L/ha (resistance management)
• No herbicidal effect - combine with a pre-emergent herbicide (eg clomazone)
Fluopyram - Summary
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 42
5. FLUENSULFONE (MCW-2) -ADAMA
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 43
1. Untreated control2. Metham sodium (STD) 60 L/ha3. Oxamyl (STD) 3 L/ha4. MCW-2 2 L/ha5. MCW-2 4 L/ha6. MCW-2 6 L/ha7. MCW-2 8 L/ha
FLUENSULFONE – FIELD TRIALS
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 44
0
2
4
6
8Un
treat
ed c
ontro
l
Met
ham
-sod
ium
std
Oxa
myl
std
MC
W-2
(2 L
/Ha)
MC
W-2
(4 L
/Ha)
MC
W-2
(6 L
/Ha)
MC
W-2
(8 L
/Ha)
Untre
ated
con
trol
Met
ham
-sod
ium
std
Oxa
myl
std
MC
W-2
(2 L
/Ha)
MC
W-2
(4 L
/Ha)
MC
W-2
(6 L
/Ha)
MC
W-2
(8 L
/Ha)
K M10 T75
Gal
l rat
ing
(0 –
8)
Root-knot nematode gall rating - 2015
ab
a a a a aaaa aaab
c
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 45
012345678
Untre
ated
con
trol
Oxa
myl
std
MC
W-2
(2 L
/Ha)
MC
W-2
(4 L
/Ha)
MC
W-2
(6 L
/Ha)
MC
W-2
(8 L
/Ha)
Untre
ated
con
trol
Oxa
myl
std
MC
W-2
(2 L
/Ha)
MC
W-2
(4 L
/Ha)
MC
W-2
(6 L
/Ha)
MC
W-2
(8 L
/Ha)
K M10 T75
Gal
l rat
ing
(0 –
8)
Root-knot nematode gall rating - 2016
a a a aaab bbb
d
c
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 46
• Registered for use
• Applied in planting water @ 2 L in 450 L /ha)
FLUENSULFONE (MCW-2) : SUMMARY
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 47
ALTERNATIVE NEMATICIDES ON TOBACCO IN ZIM CHEMICAL NAME COMMON NAME FOR USE
1. Potassium N-methyldithiocarbamate
Metham Potassium Seedbeds
2. Iodomethane Methyl iodide Seedbeds3. Tetrahydro-3,5-dimethyl-2H-
1,3,5- thiadiazine-2-thioneDazomet®/Basamid® Seedbeds
4. Sodium N-methyldithiocarbamate
Metham Sodium Seedbeds/ Field
5. Fluopyram - Bayer Velum® Field
6. Fluensulfone - Adama MCW 2 Field
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 48
NON-CHEMICAL ALTERNATIVES
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 49
NON-CHEMICAL ALTERNATIVES - SEEDBEDS
• The floating tray system
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 50
• Developed a pine bark soilless media and a float fertilizer.
• Polystyrene tray factory put up at Kutsaga.
• Growers trained on the use of the floating tray technique
200, 242 & 120 cells2:1:2Pine bark based
FLOATING TRAY SYSTEM
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 51
TRB agronomistTRB extentionist
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 52
THE FLOATING TRAY SYSTEM - ADOPTION
• Adoption rate reported to be 30-40%
• Float trays sales data show the increased use
106634
84,092
226,925
351,743359,615
0
100000
200000
300000
400000
2013 2014 2015 2016 2017
No.
of f
loat
tray
s so
ld fr
om TR
B
Year
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 53
CHALLENGE : IMPENDING BAN OF STYROFOAM PRODUCTS
• Styrofoam already banned for food packaging
• TRB searching for recyclable alternatives & factory upgrade
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 54
CULTURAL PRACTISES –CROP ROTATIONS
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 55
CROP ROTATIONS• Traditionally : tobacco - 3/4 years grass-
tobacco
• Land sizes smaller post land reform
• Need for shorter term rotation crops
• Currently bulking up seed for a Katamboragrass – effective in18 months
KATAMBORA GRASS
GHR1 VARIETY
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 56
RESISTANT VARIETIES
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 57
• All recently developed Kutsaga varieties (K RK) have varying levels of root knot nematode resistance
RESISTANT VARIETIESVARIETY RESISTANCE LEVELSVARIETY CLASSIFICATION K RK64, K RK71, K RK72, T70, T 74, T75 Very high resistance
K RK29, T73 ,T76 High resistance
K RK66, K RK26R Moderate resistance
K M10 SusceptibleKM10 T 75
ROOT GALLING IN A SUSCEPTIBLE AND RESISTANT VARIETY POST-REAPING
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 58
SUSCEPTIBLE VS RESISTANT VARS UNDER HIGH NEMATODE PRESSURE
KM10 (S)K RK66 (R)
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 59
UNFUMIGATED KM10 FUMIGATED KM10
KM10 IN LAND WITH HIGH NEMATODE PRESSURE
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 60
K RK71 IN LAND WITH HIGH NEMATODE PRESSURE
UNFUMIGATED FUMIGATEDUNFUMIGATED FUMIGATED
K RK72 IN LAND WITH HIGH NEMATODE PRESSURE
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 61
CONCLUSIONOn their own, alternatives not as effective as the fumigants.....IPM approach – has good results• Resistant varieties
• The synthetic nematicides
• Good Agricultural practices (rotations, other tobacco best practices)
THE TEAM BEHIND THE WORK
Tafadzwa Mahere Dr Cleopas ChinheyaPrivilege Makunde
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Page 62
Thank you
2018
_TW
C36
_Dim
bi.p
dfT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed