(A8)
APPLE: Malus domestica Borkhausen
MITE AIRBLAST THRESHOLD STUDY, 2007
Larry A. Hull
Fruit Research and Extension Center
Penn State University
P. O. Box 330
Biglerville, PA 17307-0330
Phone: (717) 677-6116 Ext. 6
Fax: (717) 677-4112
E-mail: [email protected]
Eric Bohnenblust
E-mail: [email protected]
European red mite (ERM): Panonychus ulmi (Koch)
Mite predator (ZM): Zetzellia mali (Ewing)
Phytoseiid mite predators (PMP): Neoseiulus fallacis (Garman), Typhlodromus pyri (Scheuten)
Twospotted spider mite (TSM): Tetranychus urticae Koch
Ten experimental and registered acaricide treatments were applied to single-tree plots in a randomized block design
consisting of two replicates of ‘Delicious,’ one replicate of ‘Golden Delicious’ and two replicates of ‘Yorking.’ The
blocking factors were pre-treatment levels of ERM and cultivar. All trees were planted to a spacing of 20 × 30 ft and were 8
yr old. All treatments were applied with a Durand-Wayland sprayer calibrated to deliver 100 gpa, driven at 2.4 mph for a
complete spray. All treatments were applied initially on 3 Jul. All plots received a regular maintenance schedule of
fungicides (Dithane 75DF, Nova 40WP, Topsin M 85DF, and Ziram 76WP) and nutrients (CaCl). Post-bloom insecticides
(Assail 70WP, Guthion 50WP, Imidan 70WP, Intrepid 2F, Rimon 0.83EC) were applied as needed at 1- to 2-wk intervals
beginning at petal-fall in early May. Effectiveness of the treatments on ERM, TS, PMP and ZM was evaluated by counting
the mites at approximately weekly intervals during the season on samples of 25 leaves/tree, or 125 leaves/treatment. The
cumulative number of mite days was determined for each treatment from 3 Jul through 17 Aug. Data were analyzed with
aANOVA and mean separation using Fisher’s Protected LSD test. Appropriate transformations (e.g., log, square root,
arcsine) were used if necessary. Pest pressure was low to moderate throughout the study.
At 3 d post application, the treatment of V10141 2.8EC had the lowest ERM population. At 10 d post application (13 Jul)
all acaricide treatments except for Apollo SC, Nexter 75WP, and the low rate of GWN-1715 75WP + GWN-1563 50WP
had reduced ERM populations below the untreated check (Table 1). By 3 Aug (31 days post application), only the
treatments of Zeal 72WDG, Envidor 240SC, Portal 0.4EC, and the high rate of GWN-1715 + GWN-1563 had reduced the
ERM populations below the untreated check (Table 1). On 17 Aug (45 days post application), Envidor was the only
treatment that had a significantly lower ERM population (Table 1). The treatment of Apollo never achieved control of ERM
during the study. By 3 Aug, ERM populations had risen in the Nexter treatment. Portal and Envidor were the most effective
treatments of ERM and had the lowest number of cumulative mite days (Table 1). The treatments of Kanemite, Zeal,
V10141 and the low rate of GWN-1715 + GWN 1563 were also effective at controlling ERM and had cumulative mite day
levels that were significantly lower than the untreated check. The Portal treatment consistently allowed the fewest number
of ERM eggs (Table 2). There was no difference between any of the treatments on PMP population levels (Table 3). All
treatments, except for the Nexter treatment on 10 Aug, significantly lowered TSM populations (Table 4). Kanemite allowed
the highest survival of ZM populations (Table 4).
Table 1.
ERM/leaf
Treatment/
formulation
Zeal 72WDG
V10141 2.8EC
Apollo SC
Kanemite 1.25SC +
Choice
Envidor 240SC
Portal 0.4EC
Nexter 75WP
GWN-1715 75WP +
GWN-1563 50WP
GWN-1715 75WP +
GWN-1563 50WP
GWN-1715 75WP +
GWN-1563 50WP
Untreated check
Rate
Amt/acre
57 g
562 ml
118 ml
917 ml +
946 ml
533 ml
946 ml
125 g
85 g +
85 g
57 g +
85 g
57 g +
57 g
---
lbs
AI/A
0.09
0.4158
0.125
0.303 +
0.25%
0.282
0.1
0.207
0.140 +
0.0937
0.094 +
0.0937
0.094 +
0.063
20 Jul 27 Jul
Cum.
3 Aug 10 Aug 17 Aug mite days
1.5b
0.1a
6.5d
1.5abc
1.2ab
6.2e
1.0a
0.9a
5.2c
1.0a
1.0abc
3.1bcd 1.5abc
4.7d
2.2c
1.4abc 72.1abc
5.0e
78.1bc
3.5de 212.7e
1.8ab
2.2abc
1.5ab
2.4abc
0.8ab
1.1ab
0.6ab
2.2bc
1.4ab
1.2ab
0.5a
3.7cde
0.5a
0.4a
0.4a
4.2c
1.8ab
0.6a
0.6a
8.1e
2.6abc
0.4ab
0.3a
6.2d
0.8ab
0.2a
0.5ab
7.9f
66.6abc
44.0ab
36.5a
227.4e
5.4a
1.5ab
1.8b
2.3bc
1.7ab 0.9a
2.2c
3.4de
89.6bcd
5.3a
3.7bc
1.9b
2.8bcd
2.1ab 4.2cd
2.4bc
4.1cde 134.0cd
5.6a
5.4a
1.6ab
4.8c
2.8bc
4.9cd
3.8bcd
6.6de
1.8ab 1.8abc 1.4abc
3.2bc 3.3bcd 1.4abc
2 Jul
6 Jul
13 Jul
5.6a
5.0a
5.0a
3.2bc
1.0a
4.4c
5.0a
5.4a
5.2a
5.6a
Means followed by the same letter(s) are not significantly different, (Fisher’s Protected LSD, P < 0.05).
Table 2.
ERM eggs/leaf
Treatment/
formulation
Rate
Amt/acre
Zeal 72WDG
V10141 2.8EC
Apollo SC
Kanemite 1.25SC +
Choice
Envidor 240SC
Portal 0.4EC
Nexter 75WP
GWN-1715 75WP +
GWN-1563 50WP
GWN-1715 75WP +
GWN-1563 50WP
GWN-1715 75WP +
GWN-1563 50WP
Untreated check
57 g
562 ml
118 ml
917 ml +
946 ml
533 ml
946 ml
125 g
85 g +
85 g
57 g +
85 g
57 g +
57 g
---
6 Jul 13 Jul
20 Jul
27 Jul
3 Aug 10 Aug
17 Aug
13.4a 17.8c
13.2a
10.7a 9.2ab 14.2a
9.5a 12.2bc 21.1a
8.0a
6.7a
9.0a
12.6e
10.4bc
9.9de
11.2de 11.6bc 14.6ef
11.2cde 10.8abc 14.3ef
10.2a
7.2a
7.1a
12.1a
5.0a 11.3a
4.8a
9.4a
6.0ab 8.0a
7.4ab 14.4a
4.1a
3.4a
3.7a
7.8a
5.4abc 6.0ab
5.8ab
4.6a
4.0a
3.8a
12.1de 16.6c
4.5a
10.0a
5.6a
4.4a
5.2ab
9.5cde
11.0a
6.5ab 14.1a
4.9a
10.0b-e
7.9abc
7.4bcd
9.0a
7.2a
5.7ab 12.2a
6.9ab 14.0a
5.9a
5.7a
7.0a-d
6.3a-d
3.9a
3.6a
6.8a-d
4.6a-d
8.7a
4.3abc
2.4a
4.0ab
20.0f
Means followed by the same letter(s) are not significantly different, (Fisher’s Protected LSD,
P < 0.05).
Table 3.
PMP/leaf
Treatment/
formulation
Rate
Amt/acre
Zeal 72WDG
V10141 2.8EC
Apollo SC
Kanemite 1.25SC +
Choice
Envidor 240SC
Portal 0.4EC
Nexter 75WP
GWN-1715 75WP +
GWN-1563 50WP
GWN-1715 75WP +
GWN-1563 50WP
GWN-1715 75WP +
GWN-1563 50WP
Untreated check
57 g
562 ml
118 ml
917 ml +
946 ml
533 ml
946 ml
125 g
85 g +
85 g
57 g +
85 g
57 g +
57 g
---
6 Jul 13 Jul
20 Jul
27 Jul
3 Aug 10 Aug
17 Aug
0.2a
0.0a
0.0a
0.3a
0.0a
0.3a
0.3a
0.0a
0.3a
0.2a
0.0a
0.4a
0.1a
0.0a
0.3a
0.1a
0.0a
0.1a
0.1a
0.1a
0.1a
0.0a
0.2a
0.2a
0.2a
0.2a
0.2a
0.1a
0.2a
0.2a
0.4a
0.2a
0.2a
0.0a
0.2a
0.1a
0.3a
0.2a
0.2a
0.3a
0.2a
0.1a
0.0a
0.2a
0.2a
0.0a
0.1a
0.0a
0.3a
0.2a
0.2a
0.1a
0.2a
0.2a
0.0a
0.0a
0.2a
0.2a
0.3a
0.2a
0.3a
0.2a
0.0a
0.1a
0.3a
0.2a
0.4a
0.2a
0.5a
0.2a
0.6a
0.4a
0.3a
0.3a
0.4a
0.1a
0.2a
Means followed by the same letter(s) are not significantly different, (Fisher’s Protected LSD,
P < 0.05).
1.6bcd 91.8bc
1.6bcd 154.7de
Table 4.
Treatment/
formulation
ZM/leaf
TS/leaf
Rate
Amt/acre 20 Jul 27 Jul 3 Aug 10 Aug 17 Aug 10 Aug 17 Aug
Zeal 72WDG
V10141 2.8EC
Apollo SC
Kanemite 1.25SC +
Choice
Envidor 240SC
Portal 0.4EC
Nexter 75WP
GWN-1715 75WP +
GWN-1563 50WP
GWN-1715 75WP +
GWN-1563 50WP
GWN-1715 75WP +
GWN-1563 50WP
Untreated check
57 g
562 ml
118 ml
917 ml +
946 ml
533 ml
946 ml
125 g
85 g +
85 g
57 g +
85 g
57 g +
57 g
---
0.1a
0.0a
0.1a
0.0a
0.0a
0.1a
0.0c
0.0c
0.0bc
0.0b
0.0b
0.0b
0.0b
0.0b
0.0b
0.0a
0.0a
0.0a
0.0a
0.0a
0.0a
0.2a
0.2a
0.0a
0.0a
0.0a
0.0a
0.0a
0.0a
0.2ab
0.0c
0.0c
0.0c
0.2b
0.0b
0.0b
0.0b
0.3a
0.0b
0.0b
0.1ab
0.0a
0.0a
0.0a
0.5ab
0.2a
0.0a
0.0a
0.6a
0.1a
0.1a
0.0bc
0.0b
0.0b
0.0a
0.1a
0.0a
0.0a
0.0bc
0.0b
0.0b
0.0a
0.0a
0.0a
0.3a
0.0a
0.1a
0.0c
0.3a
0.0b
0.6a
0.1ab
0.3a
0.0a
1.0b
0.0a
0.6a
Means followed by the same letter(s) are not significantly different, (Fisher’s Protected LSD,
P < 0.05).