Integrating mowing as a weed management tool for control of

15 Pages·2013·1.7 MB·English

Integrating mowing as a weed management
tool for control of Ambrosia artemisiifolia
in carrots
Diane Lyse Benoit, Sylvain Fortin & Manon Bélanger
Agriculture and Agri-Food Canada,
Horticultural Research and Development Centre
Saint-Jean-sur-Richelieu (Quebec) Canada
Problematics of weed control in carrots
• Carrot production mainly in
organic soil (~85%OM)
• Ambrosia artemisiifolia L.
(common ragweed)
– most important weed difficult to
control
• Linuron - only herbicide
registered for last 30 years
• First report of linuron
resistance in ragweed in
Canada
Morphological difference between carrot and A. artemisiifolia
Alternative approach:
CARROT WEED
CS5
CS4
CS3
CS2
CS1
Experimental protocol - Growth cabinet

• CR design with 2 replicates
– 25 C day and 15 C night
– photoperiod of 16 hr day and 8 hr night
– 6 seedlings per pot
• Weeds species – AMBEL & AMARE
• Carrot cultivars – SugarSnax & Apache
• Parameters measured
– plant height (before & after cut)
– Cutting height
– Number of leaves and branches (7 d interval after cut)
Height vs Stage (carrot / weeds) - Control
4L / 8L
) 3L / 6L
s
d
e
e
w

/

t
o
2L / 4L
r
r
a
c

(

e
g
a
t
S 1L / 2L
Amare
Ambel
Apache
cot Sugarsnax
0 5 10 15 20 25 30
Hauteur (cm)
Regrowth following cutting at 1st internode (CS3)
(Carrot stage / weed stage)
ambel leaves
6
amare branches
ambel branches
s
e 5 apache leaves
h
c
n sugarsnax leaves
a
rb 4
/
s
e
v
a 3
e
l w
e
n
# 2

n
a
e
M
1
0
2L / 4L 3L / 6L 4L / 8L
Growth stage at cutting
AMBEL 6L, CS2 AMBEL 6L, CS3
Summary: Growth cabinet experiment
• rapidity of phenological development :
AMARE > AMBEL > > carrots w Sugarsnax > Apache
• Cv. Apache was taller & produced more leaves than
SugarSnax
• Cutting above the 1st internode stimulated branching to
a greater extent in AMBEL than in AMARE.
• Selective mowing could be done minimally at the 6
leaves stage of AMBEL and AMARE, approximately 27
days after seeding when carrots are at 1 to 2 leaves
stage and 6-7cm in height.
Experimental protocol - Field experiment
• CR design with 2 replicates
– 1 row/species
– 10 cm between individuals & 1 m between rows
– Monitored 4 contiguous seedlings at each stage & cutting height
• Parameters measured:
– plant height (before & after cut) ; Cutting height
– Number of leaves and branches (7 d interval after cut)

19 m
9 m
0.5m A carrot Apache
S carrot SugarSnax
AA AMBEL
10 m 23 m AR AMARE
1m
0.5m
A carrot Apache
8 m 0.5m buffer zone
Cutting Effect on Regrowth
AMARE
AMBEL
25
30
Cotyledon
20
)
m
25 2 Leaves c Cotyledon
)m 4 Leaves ( t 15 1 Leaf
c 20 hg 2 Leaves
( t 6 Leaves ieH 10 3 Leaves
hgie 15 8 Leaves nae 5 4 Leaves
H M
10
n 0
a
eM 05 Control Below Cot Above Cot1st internode2nd internode 3rd internode
Control elow Cot bove Cot nternode nternode nternode CaCrurotttin cgv H. eSiughgtarSnax
B A 1st i 2nd i 3rd i
25
Cutting Height
20
)m Cotyledon
c( th 15 12 LLeeaafves
g
ie 10 3 Leaves
H
n 4 Leaves
a 5
e
M
0
Control Below Cot Above Cot1st internode2nd internode 3rd internode
Cutting Height