Research
Row Cover results for 2003
Results
There was a clear benefit to covering the plots with Reemay, as it increased both the number and weight of melons harvested. Some of the yield benefits of these covers may have been due to a warming effect in the spring, but they also decreased the incidence of bacterial wilt, indicating that they protected the plants from cucumber beetles. The row covers delayed the first onset of bacterial wilt by three weeks in Ames and one week in Muscatine.
This result was very
surprising, as more beetles should lead to more disease, and more disease
should lead to dead plants and fewer melons.
One reason this may have occurred is the fairly low populations and seemingly
late arrivals of striped and spotted cucumber beetles in Iowa this year.
Perhaps a certain population of beetles or early epidemics of bacterial
wilt are necessary to affect yield.
We look forward to testing these insecticides next year, when beetle
populations may be higher.
Yield, beetle populations, and disease incidence in a single row of 12 melon plants in row-covered and uncovered fields at Ames, Lewis, and Muscatine, Iowa.
|
Treatment
|
Number
|
Weight
(lb)
|
Striped
(mean
per plot)
|
Spotted
(mean
per plot)
|
Wilt
(mean
plants/plot)
|
|
Row-covered
|
21.69
a
|
122.77
a
|
0.069
a
|
0.060
a
|
0.366
a
|
|
Uncovered
|
14.64
b
|
86.19
b
|
0.041
b
|
0.043
b
|
0.126
b
|
|
LSD
(P<0.05)
|
2.78
|
13.06
|
0.013
|
0.012
|
0.038
|
Of the insecticide treatments evaluated, none resulted in yields greater than the untreated control. In fact, plots treated with the attractant (Invite) + an organically-approved insecticide (boric acid) had lower yields than the control. Furthermore, attempts to find a correlation between yield and either beetle populations or bacterial wilt incidence for the insecticides failed. This means that, although the insecticides sometimes reduced beetle populations or bacterial wilt below the levels found for the control, these reductions did not always lead to higher yield.
Yield,
beetle populations, and disease incidence in a single row of 12 melon plants
treated with insecticides at Ames, Lewis, and Muscatine, Iowa.
|
Treatment
|
Number
|
Weight
(lb)
|
Striped
(mean
per plot)
|
Spotted
(mean
per plot)
|
Wilt
(mean
plants/plot)
|
|
Admire
|
19.75
a
|
114.95
a
|
0.057
abc
|
0.06
|
0.05
d
|
|
Entrust
|
17.08
ab
|
97.89
ab
|
0.08
a
|
0.06
|
0.17
c
|
|
Invite+Sevin
|
21.29
a
|
116.77
a
|
0.05
bc
|
0.05
|
0.29
b
|
|
Invite+BoricAcid
|
13.33
b
|
77.4
b
|
0.05
bc
|
0.04
|
0.44
a
|
|
Sevin
|
20.17
a
|
119.25
a
|
0.03
c
|
0.04
|
0.22
bc
|
|
Control
|
17.37
ab
|
100.62
a
|
0.06
ab
|
0.05
|
0.276
b
|
|
LSD
(P<0.05)
|
4.82
|
22.62
|
0.02
|
-
|
0.07
|