کاهش خسارت خشکسالی در گندم دیم

Peach -- Powdery Mildew   Cause: Podosphaera pannosa (formerly Sphaerotheca pannosa) and Podosphaera clandestina, fungi that overwinter on infected twigs, shoots, and buds of stone fruits. Leaves are infected as they emerge from the bud. Colonies that develop on leaves produce airborne conidia that infect other leaves and fruit. Fruit are susceptible to infection until pit hardening. Roses are another host and may increase disease pressure if planted nearby. A disease called rusty spot is associated with nearby apple orchards infected with apple powdery mildew, Podosphaera leucotricha. Peach or nectarine fruit closest to these apple orchards had a higher incidence of rusty spot. Removing an adjacent apple orchard has reduced rusty spot in peach orchards. Symptoms: Terminal growth, including twigs, leaves, and shoots, shows a white mildew in spring and early summer, often resulting in twig distortion. On fruit, powdery mildew develops as a fine white mold on the peach surface. Later in the season, affected peaches take on a whitish russetted appearance and may also be malformed and scabby. Nectarine fruit is very susceptible. Rusty spot is characterized by small, round, orange-tan lesions which gradually enlarge as the fruit enlarges. Fungal mycelium is rarely seen in these lesions. Several colonies of powdery mildew can be seen on these Elberta peaches. Leaves may become distorted when infections are numerous. Numerous conidia can be seen on this peach leaf.   Cultural control: Remove affected plant parts during normal orchard operations such as pruning and thinning. Use resistant cultivars. Remove nearby rose or apple plantings or keep powdery mildew under control on roses and apples. Chemical control: Use at petal fall or shuck split. Then monitor orchard closely for the development of symptoms and, if found, use a product with eradicant or curative properties. Not needed after pit hardening. Abound at 11 to 15 fl oz/A. Alternate with other fungicides. Do not apply more than 4 times/year or 2 sequential sprays. May be applied the day of harvest. Sprayers used for Abound should not be used on apples such as Gala, Cox's Orange Pippin and McIntosh. 4-hr reentry. Bicarbonate-based products. Might supplement a normal program when powdery mildew is first observed. Do not mix with acidifying agents. Thorough coverage is essential. Poor to moderate control. Armicarb 100 (85% potassium bicarbonate) at 2.5 to 5 lb/100 gal water. 4-hr reentry/ Kaligreen (82% potassium bicarbonate) at 2.5 to 3 lb/A.4-hr reentry. MilStop (85% potassium bicarbonate) at 2 to 3 lb/A. 1-hr reentry. Remedy (by Bonide) is registered for home use. Elite 45 DF at 4 to 8 oz/A. Do not apply more than 3 lb/A per crop season. Can be applied up to and including day of harvest. 12-hr reentry. Gem at 4 to 8 oz/A. Rotate with other fungicides that have different modes of action. Do not apply more than twice consecutively, exceed four (4) applications, 32 oz/A/season, or within 1 day of harvest. Do not use with ogranosilicate surfactants. ‘Concord’ grapes may be injured if accidentally sprayed. 12-hr reentry. Immunox at 0.5 fl oz/gal water. May be applied up to the day of harvest. Do not use more than seven times per season. Indar 75 WSP at 2 oz/A plus a wetting agent. Do not exceed 1 lb/A/season. 12-hr reentry. JMS Stylet Oil at 1 to 2 gal/100 gal water. Do not apply micronized sulfur within 10 days of an oil application. Do not use oil within 14 days of a sulfur application. Do not use during freezing temperatures, above 90°F, or when plants are under heat or moisture stress. Do not use when foliage is wet because good coverage is essential. 4-hr reentry. O Microthiol Disperss (80% sulfur) at 10 to 20 lb/A. Do not use a spreader sticker. 24-hr reentry. Pristine at 10.5 to 14.5 oz/A. Do not use more than 2 consecutive applications or more than 5 times/year. Can be used day of harvest. 12-hr reentry. Propiconazole based fungicides are registered. Limited to 4 applications (2 during bloom and 2 before harvest). May be used up to and including day of harvest. Bumper 41.8 EC at 4 oz/A. Do not use on Stanley type Plums. 24-hr reentry. Orbit at 4 oz/A. Do not use on Stanley type Plums within 21 days of harvest. 24-hr reentry. PropiMax EC at 4 fl oz/A. Do not use on Cherry or Stanley type Plums. 24-hr reentry. Tilt at 4 oz/A. 12-hr reentry. Quilt (propiconazole + azoxystrobin) at 14 fl oz/A. Do not apply more than two (2) sequential sprays. May be applied the day of harvest. 12-hr reentry. Rally 40 WP at 2.5 to 6 oz/A. Can be applied up to day of harvest. Use Eagle 20 EW at 2 to 3 fl oz/100 gal water for landscapes. 24-hr reentry. Thiolux Jet (80% sulfur) at 10 to 30 lb/A. 24-hr reentry. Biological control: Serenade MAX (Bacillus subtilis strain QST 713) at 1 to 3 lb/A is registered for suppression only. As such it is not recommended for use in the Pacific Northwest. 4-hr reentry. References:Ogawa, J.M. et al. 1995. Compendium of Stone Fruit Diseases. St. Paul, MN: APS Press