Kai Umeda
Maricopa County Cooperative Extension
University of Arizona, Phoenix, AZ
Introduction
A survey of the 2002 melon growing seasons was conducted to ascertain the
incidences of insect pests, diseases, and occurrences of weeds. The survey
was conducted for spring and fall crops of cantaloupes, honeydews, and watermelon
grown in the state. Six crop consultants in central Arizona and in Yuma
County were sent surveys and four completed surveys were received during
November 2002. The completed surveys represented 36.5% of the state's total
cantaloupe acreage in 2002, 61.4% of the honeydew acreage, and only 15%
of the watermelon acreage (Table 1). The data for
statewide melon acreages were obtained from the Arizona Agricultural Statistics
Service for February 2003 at: http://www.nass.usda.gov/az/crops/2003/crop0221.pdf
. The spring crops of cantaloupe, honeydews, and watermelons were generally
planted during January to March 2002 with harvest conducted during May through
July. The fall cantaloupe and honeydews were planted during July to August
and harvested during September to November of 2002. No fall watermelons
were planted in 2002 in the survey. The data is presented primarily as averages
or as a range in some cases for the number of pesticide applications for
pests.
Results and Discussion
All melons were treated for insect pests in 2002 (Table
3). All melons were treated at planting time for insects and 100%
of the fall cantaloupes and honeydews were treated with a foliar insecticide,
primarily for whiteflies. Ground dwelling insects, whiteflies, and cabbage
loopers were treated in all of the melons. Ground dwelling insects in
one situation required up to five applications of insecticides. Spring
cantaloupes were sprayed once in Yuma by one respondent and no application
of insecticide in Maricopa County by another respondent. Three to four
applications were required for whiteflies in the fall cantaloupes. Spider
mites occurred in watermelons and required treatment on some acreages.
Beet armyworm also occurred but did not warrant any treatment. Leafminers
were found on fall cantaloupes and honeydews and required up to two treatments.
Aphids were not observed in 2002.
Powdery mildew occurred in all melons and accounted for most of the fungicide
applications (Table 4). Vine-decline disease affected
on 4% of the spring cantaloupe crop and up to 77% of the watermelon crop.
Vine-decline disease was not observed in any of the surveyed cantaloupes
or honeydews. In fall cantaloupes, an unidentified soil-borne disease
was observed as were other unspecified foliar diseases on honeydews and
cantaloupes. Viruses were not observed in 2002.
Over 80% of the cantaloupe and honeydew crops were treated with a herbicide
compared with fewer watermelon fields being treated (Table
5). Most of the melon acreages were treated at planting time with
few acres treated with postemergence herbicides for grass weeds. Pigweeds
and purslane were problems on 24% of the spring cantaloupe fields with
perennial grass weeds and nutsedge infesting 14% of the fall cantaloupe.
A higher percentage of watermelon fields were observed to be infested
with more weeds.
Three respondents provided estimates of melon crop yield reductions (Table
2). One respondent reported observed losses in spring cantaloupes
and watermelons, one reported only spring melons, and one reported only
fall melons. Weather conditions were cited consistently for causing melon
yield reductions. Market conditions were cited for the highest yield reductions
in spring cantaloupes and watermelons. Weeds, insects, and diseases contributed
to slight yield losses. Powdery mildew, vine-decline disease, nutsedge,
cabbage loopers, and spider mites were reasons for crop losses.
Table 1. 2002 Survey of melon acreage
in Arizona |
N=4 |
Spring cantaloupe |
Fall cantaloupe |
Spring honeydew |
Fall honeydew |
Seedless watermelon |
Seeded watermelon |
Acreage surveyed |
3303 |
2100 |
805 |
730 |
739 |
193 |
% of state total |
36.5% (14,800A) |
61.4% (2,500A) |
15% (6,200A) |
Average yield
(range) |
749 carton/A
(660-900) |
640 carton/A
(630-650) |
967 carton/A
(700-1100) |
855 carton/A
(710-1000) |
36T/A
(23-50) |
39T/A
(22-55) |
Potential yield |
750-900 |
630-750 |
1100 |
1100 |
45T |
30T |
Table 2. Observed melon percentage
yield reductions
N=2 |
Spring cantaloupe |
Fall cantaloupe |
Fall honeydew |
Seedless watermelon |
Seeded watermelon |
All factors |
24 |
15 |
10 |
7 |
27 |
Weather |
10 |
12 |
8 |
6 |
10 |
Weeds |
0 |
2 |
1 |
0 |
0 |
Insects |
~1 |
~1 |
0 |
0.5 - ~1 |
0.5 - 1 |
Diseases |
5 |
1 |
1 |
0.5 |
0.5 |
Other factors* |
9 |
0 |
0 |
0 |
16 |
*Other factors indicated was market
conditions |
Table 3. Insect pest infestations
in melons
|
Spring cantaloupe |
Fall cantaloupe |
Spring honeydew |
Fall honeydew |
Seedless watermelon |
Seeded watermelon |
Percentage of acres treated for
insects |
100 |
100 |
100 |
100 |
100 |
100 |
Percentage of acres treated for insects
at planting |
100 |
100 |
100 |
100 |
100 |
100 |
Percentage of acres treated for insects
by foliar application |
24 |
100 |
13 |
100 |
95 |
100 |
Percentage infested by ground
dwelling insects |
65 |
48 |
30 |
24 |
38 |
74 |
Percentage of acres treated for this
pest |
65 |
48 |
30 |
24 |
38 |
74 |
Number of pesticide applications required
to control this pest |
1 - 5 |
0 -
5 |
1 - 5 |
0 - 5 |
0 - 2 |
0 - 2 |
Percent reduction in yield due to this
pest |
0 - 2 |
0 |
0 |
0 |
0 |
0 |
Percentage of acres infested by
whiteflies |
39 |
100 |
13 |
100 |
95 |
100 |
Percentage of acres treated for this
pest |
24 |
100 |
13 |
100 |
76 |
64 |
Number of pesticide applications required
to control this pest |
0 - 1 |
3 - 4 |
1 |
1 - 4 |
1 |
1 |
Percent reduction in yield due to this
pest |
0 |
0 |
0 |
0 |
~1% |
0
|
Percentage of acres infested by cabbage
loopers |
22 |
24 |
8 |
41 |
40 |
45 |
Percentage of acres treated for this
pest |
17 |
24 |
8 |
41 |
30 |
26 |
Number of pesticide applications required
to control this pest |
0 - 1 |
0 - 2 |
0 - 1 |
0 - 2 |
0 - 1 |
0 - 1 |
Percent reduction in yield due to this
pest |
~1% |
0
|
~1% |
0
|
~1% |
~1%
|
Percentage of acres infested by spider
mites |
2 |
3 |
0 |
0 |
38 |
74 |
Percentage of acres treated for this
pest |
0 |
0 |
0 |
0 |
38 |
74 |
Number of pesticide applications required
to control this pest |
0 |
0 |
0 |
0 |
0 - 1 |
0 - 1 |
Percent reduction in yield due to this
pest |
0 |
0 |
0 |
0 |
0.50% |
0.50% |
Percentage of acres infested by beet
armyworm |
0 |
0 |
0 |
0 |
4 |
7 |
Percentage of acres treated for this
pest |
0 |
0 |
0 |
0 |
0 |
0 |
Number of pesticide applications required
to control this pest |
0 |
0 |
0 |
0 |
0 |
0 |
Percent reduction in yield due to this
pest |
0 |
0 |
0 |
0 |
0 |
0 |
Percentage of acres infested by leafminers |
5 |
57 |
0 |
28 |
0 |
0 |
Percentage of acres treated for this
pest |
0 |
57 |
0 |
28 |
0 |
0 |
Number of pesticide applications required
to control this pest |
0 |
0 - 2 |
0 |
0 - 2 |
0 |
0 |
Percent reduction in yield due to this
pest |
0 |
0 |
0 |
0 |
0 |
0 |
Percentage of acres infested by aphids |
0 |
0 |
0 |
0 |
0 |
0 |
Percentage of acres treated for this
pest |
0 |
0 |
0 |
0 |
0 |
0 |
Number of pesticide applications required
to control this pest |
0 |
0 |
0 |
0 |
0 |
0 |
Percent reduction in yield due to this
pest |
0 |
0 |
0 |
0 |
0 |
0 |
Table. 4
Disease incidence in melons
|
Spring
Cantaloupe |
Fall
Cantaloupe |
Spring
Honeydew |
Fall
Honeydew |
Seedless Watermelon |
Seeded Watermelon |
Percentage of
acres treated for diseases |
42 |
100 |
100 |
100 |
95 |
100 |
Percentage of
acres treated for diseases at planting |
0 |
90 |
0 |
0 |
0 |
0 |
Percentage of
acres treated for diseases by foliar application |
42 |
100 |
100 |
100 |
58 |
50 |
Percentage of
acres infected by unidentified soil-borne diseases |
0 |
90 |
0 |
0 |
0 |
0 |
Percentage of
acres treated for this disease |
0 |
0 |
0 |
0 |
0 |
0 |
Number of pesticide
applications required to control this disease |
0 |
0 |
0 |
0 |
0 |
0 |
Percent reduction
in yield due to this disease |
0 |
0 |
0 |
0 |
0 |
0 |
Percentage of
acres infected by seedling soil-borne diseases |
0 |
0 |
0 |
0 |
0 |
0 |
Percentage r
of acres treated for this disease |
0 |
0 |
0 |
0 |
0 |
0 |
Number of pesticide
applications required to control this disease |
0 |
0 |
0 |
0 |
0 |
0 |
Percent reduction
in yield due to this disease |
0 |
0 |
0 |
0 |
0 |
0 |
Percentage of
acres infected by vine decline soil-borne diseases |
4 |
0 |
0 |
0 |
20 |
77 |
Percentage of
acres treated for this disease |
0 |
0 |
0 |
0 |
0 |
0 |
Number of pesticide
applications required to control this disease |
0 |
0 |
0 |
0 |
0 |
0 |
Percent reduction
in yield due to this disease |
1% |
0 |
0 |
0 |
0.50% |
0.50% |
Percentage of
acres infected by powdery mildew |
42 |
100 |
100 |
100 |
58 |
50 |
Percentage of
acres treated for this disease |
42 |
100 |
100 |
100 |
58 |
50 |
Number of pesticide
applications required to control this disease |
1 |
2
- 3 |
1 |
2 |
1
- 2 |
2 |
Percent reduction
in yield due to this disease |
4% |
1% |
0 |
1% |
0 |
0 |
Percentage of
acres infected by other foliar diseases |
0 |
33 |
0 |
41 |
0 |
0 |
Percentage of
acres treated for this disease |
0 |
33 |
0 |
41 |
0 |
0 |
Number of pesticide
applications required to control this disease |
0 |
1 |
0 |
1 |
0 |
0 |
Percent reduction
in yield due to this disease |
0 |
0 |
0 |
0 |
0 |
0 |
Percentage of
acres infected by viruses |
0 |
0 |
0 |
0 |
0 |
0 |
Percent reduction
in yield due to this disease |
0 |
0 |
0 |
0 |
0 |
0 |
Table. 5
Weed incidence in melons
|
Spring
Cantaloupe |
Fall
Cantaloupe |
Spring
Honeydew |
Fall
Honeydew |
Seedless Watermelon |
Seeded Watermelon |
Percentage of
acres treated for weeds |
82 |
90 |
95 |
96 |
42 |
74 |
Percentage of
acres treated for weeds at planting |
82 |
90 |
95 |
96 |
42 |
74 |
Percentage of
acres treated for weeds by foliar application |
21 |
14 |
27 |
21 |
0 |
0 |
Percentage of
acres infested by annual grass weeds |
20 |
0 |
2 |
0 |
38 |
74 |
Percentage of
acres infested by perennial grass weeds |
15 |
14 |
19 |
21 |
0 |
0 |
Percentage of
acres treated for grass weeds at planting |
24 |
14 |
16 |
0 |
38 |
74 |
Percentage of
acres treated for grass weeds postemergence |
15 |
14 |
19 |
21 |
0 |
0 |
Percent reduction
in yield due to annual grass weeds |
0 |
0 |
0 |
0 |
0 |
0 |
Percent reduction
in yield due to perennial grass weeds |
0 |
0 |
0 |
0 |
0 |
0 |
Percentage of
acres infested by pigweeds |
24 |
0 |
8 |
0 |
38 |
74 |
Percent reduction
in yield due to pigweeds |
0 |
0 |
0 |
0 |
0 |
0 |
Percentage of
acres infested by nutsedge |
9 |
14 |
0 |
0 |
8 |
15 |
Percent reduction
in yield due to nutsedge |
0 |
2% |
0 |
0 |
0 |
0 |
Percentage of
acres infested by groundcherry |
18 |
0 |
0 |
0 |
38 |
74 |
Percent reduction
in yield due to groundcherry |
0 |
0 |
0 |
0 |
0 |
0 |
Percentage of
acres infested by purslane |
24 |
0 |
8 |
0 |
38 |
74 |
Percent reduction
in yield due to purslane |
0 |
0 |
0 |
0 |
0 |
0 |
Percentage of
acres infested by other broadleaved weeds |
18 |
0 |
0 |
0 |
38 |
74 |
Percentage of
acres treated for broadleaved weeds at planting |
24 |
14 |
16 |
0 |
38 |
74 |
Percent reduction
in yield due to other broadleaved weeds |
0 |
0 |
0 |
0 |
0 |
0 |
|
Full Disclaimers
Issued in furtherance of Cooperative Extension work, acts
of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture,
James A. Christenson, Director Cooperative Extension, College of Agriculture
and Life Sciences, The University of Arizona.
The University of Arizona is an equal opportunity, affirmative
action institution. The University does not discriminate on the basis of race,
color, religion, sex, national origin, age, disability, veteran status, or sexual
orientation in its programs and activities.
Any products, services, or organizations that are
mentioned, shown, or indirectly implied in this web document do not imply
endorsement by The University of Arizona.
Information provided by:
Kai Umeda, kumeda@ag.arizona.edu Area Extension Agent,
Vegetable Crops
University of Arizona, Tucson, Arizona.
Material written 2003. |