Table 13 - Characteristics of Apple Scab Fungicides*
|
Fungicide and Rate/100 Gallons Dilute |
Protection |
Retention |
Re- distribution |
Hour Post-Infection Activity |
Pre- symptom |
Post- symptom |
|
Benlate (benomyl)1 50WP, 3 ozs. |
F |
P-F |
P-F |
18-24 |
E |
VG |
|
Captan 50WP, 2 lbs. |
VG |
VG |
G |
18-24 |
none |
none |
|
Carbamate (ferbam) 76WP, 2 lbs. |
G |
G |
G |
none |
none |
none |
|
Dithane (mancozeb) M-45, DF |
VG |
VG |
G |
18-24 |
none |
P |
|
Maneb (maneb) 75DF, 1.5 lbs. |
VG |
VG |
G |
18-24 |
none |
none |
|
Manzate, Penncozeb (mancozeb) 80W, 75DF 1.5 lbs. |
VG |
VG |
G |
18-24 |
none |
none |
|
Nova (myclobutanil) 40W, 2 ozs. |
F |
F? |
F? |
72-96 |
E |
F-G |
|
Polyram (metiram) 80WP 1.5 lbs. |
G |
G |
G |
18-24 |
none |
none |
|
Procure (triflumizole) 50WS 4 ozs. |
F |
P |
P |
72-96 |
E |
F-G |
|
Rubigan (fenarimol) 1EC, 4 fl. ozs. |
F |
P |
P |
72-96 |
E |
F-G |
|
sulfur, 5 lb s. actual |
F |
F-G |
F-G |
none |
none |
none |
|
Syllit (dodine)1 65WP, 1/2 lb. |
VG |
VG |
G |
18-24 |
E |
VG |
|
Thiram 65WP, 2 lbs. |
F |
F |
F |
15-20 |
none |
none |
|
Topsin-M (thiophanate-methyl)1 70WP, 6 ozs. |
F |
P-F |
P-F |
18-24 |
E |
VG |
Key: P = poor, F = fair, G = good, VG = very good, E = excellent.
1 - Not effective against resistant strains of the fungus.
* Adapted from: 1996 Pest Management Recommendations for Commercial Tree-Fruit Production by , A.M Agnello, W.F. Wilcox, J. Kovach, and W.C. Stiles, Cornell Cooperative Extension.
Protection:
Ability of a fungicide to kill or inactivate scab spores and prevent infection when the fungicide residue is present before an infection period occurs.Retention:
Ability to resist excessive wash-off by rain so that residue provides satisfactory scab protection.Redistribution:
Ability of a fungicide, which has been sprayed on leaves and fruit, to be washed by rains to unsprayed parts or to new growth developed after the spray was applied, thus providing protection against scab.Post-Infection Activity
(also called "Kickback"): Ability of a fungicide to kill or stop fungal growth and to prevent the establishment of scab lesions when applied within a given number of hours from the beginning of a scab infection period. The number of hours of post-infection activity given are accurate at average temperatures of 50-60oF. At a lower average temperature, the period of post-infection activity for a fungicide may be longer than as given in the table.Pre-Symptom Activity:
When applied beyond the time limit for Post-Infection activity, a fungicide with Pre-symptom activity will allow small yellowish-green scab lesions to develop, but will inhibit the production of secondary spores from those lesions. This will reduce the spread of secondary scab.Post-Symptom Activity
(also called "Burnout" or "Eradication"): Ability of a fungicide to prevent or inhibit the further production of secondary scab spores when applied to sporulating (active) lesions. Such applications do not kill the scab fungus, but merely suppress its development. The applications must be repeated to maintain this suppression. As with Pre-symptom activity, reducing the number of secondary scab spores reduces the spread of secondary scab.On to Fungicide Options for Flyspeck