2/18/2016
Biological Control of Mile-a-Minute
Weed: Effects of Abiotic
Environmental Conditions
Mile-a-minute weed: Persicaria
perfoliata (Polygonaceae)
J. Hough-Goldstein, E.C. Lake, and S.H. Berg
Entomology & Wildlife Ecology
University of Delaware
Photo: Yun Wu
Forest edge, disturbed open areas
Pea Patch Island, Delaware, Aug. 2003
White Clay Creek State Park, July, 2003
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Native to Asia:
China
Japan
Korea
India
Bangladesh
Nepal
Bhutan
Burma (Myanmar)
Thailand
Vietnam
the Malay Peninsula
Taiwan
the Philippines
Also found in:
Turkey
eastern Russia
Biological Control Program –
US Forest Service, 1996
MAM in US (Les Mehrhoff, Conn., IPANE)
Mile-a-minute weevil - 2004
Rhinoncomimus latipes
MAM in China (Ding Jianqing, Wuhan Botanical
Garden)
M. Frye
Mile-a-minute weevil
Three release sites intensively monitored
2005 – 2010 (E. Lake, PhD 2011)
E. Lake
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Percent
cover
AB
d
ABC
b
BC
a
D
c
Percent
cover
Weevils/ m2
MAM
D
c
A
d
C
c
Lake et al. 2011.
Biological Control
17-May
17-May
17-Jun 17-Jul
17-Aug
17-Sep
Weevils/ m2
MAM
17-Jun 17-Jul
17-Aug
17-Sep
17-Oct
17-Oct
West Chester, PA total monthly
precipitation
Scott Berg – moisture/weevils
factorial expt. (2012 and 2013)
Does a wet spring favor weed over weevil?
MAM biomass (2013)
Seeds produced (2013)
Effect
p-value
Effect
p-value
Water
<0.001*
Water
<0.001*
Weevil
0.036*
Weevil
<0.001*
Water x weevil
0.908
Water x weevil
<0.001*
High water
High water
Low water
Low water
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West Chester, PA mean monthly
temperature (°F)
Summer 2014:
Temperature effects on insect
80
• Development time from egg to adult
75
– 20°C: 35-39 days
– 25°C: 21-23 days
– 30°C: 19 days
70
2008
65
2009
60
2010
55
50
April
May
June
July
August
Does a warm spring and summer favor
weevil over weed?
Temperature effect on
development rate
• Number of generations could vary from
~2.5 to more than 5 during spring and
summer
Population model
• Egg to adult, avg. 358 Degree Days
(base temp. 10.2 °C)
• Preoviposition period avg. 139 DD
(base temp. 10.2 °C)
• Population model applied to 3 years of
field data, 2008 – 2010
Lower developmental threshold: 10.2 °C
Assumptions of model:
In field, egg-laying stops in late
August – mid-September
• Overwintered weevils start laying eggs
May 15
• Each female lays 2 eggs per day for 50
days (100 total); half female
• Egg to adult: 358 DD (base 10°C)
• New adults start laying eggs:139 DD
• Egg-laying stops when <358 DD remain:
“egg-laying cut-off ”
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Dates that DD targets met:
“Egg-laying cut-off,” SE
Pennsylvania
2008
2009
June 18
June 21
June 28
July 1
July 21
July 29
July 16 Second gen. new adults
July 30
Aug. 8
July 24 First new eggs
Aug. 26
Sept. 1
Aug. 16 Third gen. new adults
Sept. 5 Sept. 15*
Oct. 16
2010 (Eggs laid on 15 May)
June 15 First gen. new adults
One female
(2008)
XXX
Sept. 24 Fourth gen. new adults
*After egg-laying cut-off
18-Jul
19-Jul
65
66
2
2
42
44
20-Jul
21-Jul
22-Jul
23-Jul
24-Jul
25-Jul
26-Jul
27-Jul
28-Jul
67
68
69
70
71
72
73
74
75
2
2
2
2
2
2
2
2
2
46 2nd gen new adults
48
2 First adult emerges 21 July
50
4 Same numbers of adults as first gen. eggs (assumes that all survive)
52
6
54
8
56
10
58
12
60
14
62
16
29-Jul
30-Jul
31-Jul
1-Aug
2-Aug
3-Aug
4-Aug
5-Aug
6-Aug
7-Aug
8-Aug
9-Aug
10-Aug
11-Aug
12-Aug
13-Aug
14-Aug
15-Aug
16-Aug
17-Aug
18-Aug
19-Aug
20-Aug
21-Aug
22-Aug
23-Aug
24-Aug
76
77
78
79
80
81
82
83
84
85 Total:
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
25-Aug
103
82
26-Aug
104
80
2
2
2
2
2
2
2
2
2
100
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
96
98
100
98
96
94
92
90
88
86
84
18 2nd gen. new eggs
20
2 First female begins laying 30 July, continues for 50 days or until "cut-off" date*
22
6 Each day add 2 eggs each from each new female
24
12
26
20
only half are female, but each female lays 2 eggs)
28
30
30
42
32
56
34
72
36
90
38 110
40 132
42 156
44 182
46 210
48 240
50 272
52 306
54 342 After 50 days, the first adult from the first generation quits laying eggs
56 380
58 420
60 462
62 506
64 552
66 600
68 650
70 702
3rd
gen.
new
72 756 adults
begin emerging 26
74 812
2 Aug.
Generation
First
Second
Fourth
• 2009: Sept. 4
• 2010: Sept. 8
Aug. 26 First new eggs
Date, day, eggs and adults for each generation
Model:
Third
• 2008: Sept. 7
June 24 First new eggs
New adults begin to emerge
2008
2009
2010
June 18
June 21
June 15
Number of new adults
100
100
100
Egg-laying begins
June 28
July 1
June 24
New adults begin to emerge
July 21
July 29
July 16
Number of new adults
4,244
3,878
4,494
Egg-laying begins
July 30
Aug. 8
July 24
New adults begin to emerge
Aug. 26
Sept. 1
Aug. 16
Number of new adults
22,960
8,120
36,848
Egg-laying begins
Sept. 5
New adults begin to emerge
Oct. 16
xxx
Sept. 24
Number of new adults
30
0
4,760
Total number of new adults
3-Sep
112
64
90
1332
4-Sep
113
62
92
1406
5-Sep
6-Sep
7-Sep
114
115
116
60
58
56
94
96
98
1482
1560
1640
90
110 3rd gen. new eggs
First female begins laying on Sept. 5, continues until
132
2 "cut-off" date*
156
8
182
20 *Egg-laying cut-off: Sept. 7, 2008
Only these have enough DD to make it to adult by Oct.
31:
210
8-Sep
117
100
9-Sep
10-Sep
11-Sep
118
119
120
98
96
94
240
272
306
12-Sep
121
92
342
13-Sep
122
90
380
14-Sep
123
88
420
15-Sep
124
86
462
16-Sep
125
84
506
17-Sep
126
82
552
18-Sep
127
80
600
19-Sep
128
78
650
20-Sep
129
76
702
21-Sep
130
74
756
22-Sep
131
72
812
23-Sep
132
70
24-Sep
25-Sep
133
134
68
66
930
992
26-Sep
27-Sep
28-Sep
29-Sep
30-Sep
1-Oct
135
136
137
138
139
140
64
62
60
58
56
4244
1056
1122
1190
1260
1332
1406
2-Oct
141
3-Oct
142
4-Oct
5-Oct
143
144
Total:
Need 358 DD from egg to adult
Sept. 7 - Oct. 31:
359
Sept. 8 - Oct. 31
346
870
Total number of adults produced:
Generation:
First
Second
Third
Fourth
Total:
100
4244
22,960
30
27,334
1482
1560
Total:
1640
22,960
2009 a “perfect storm”
• High moisture in spring
• Low temperatures throughout late spring &
summer
(Sept. 15) Aug. 26
27,334 12,098 46,202
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Summary
Management Implications
• Abiotic factors that impact mile-aminute status:
–Moisture
• Vine growth
–Temperature
• Herbivore population growth
Acknowledgements
Lab Group 2012
Scott Berg
Kaity Handley
Jeff Smith
Amanda Stout
Kiri Cutting
Sam Nestory
Lab Group 2008
Matt Frye
Kelsey Paras
Ellen Lake
Rachel Schnaitman
Shane LaCoss
Questions?
Brian O’Neill
Dick Reardon
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