Spray strategies to control Anthracnose fruit rot in day-neutral strawberries, 1994
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Day-neutral strawberries were planted on 17 and 18 May 1994 in sand loam soil (fine , loamy, mixed mesic, Typic Hapludoll) at the Iowa Stale University Ho11iculture Faim near Gilbert, IA. Plants were spaced I ft apart in double rows with S ft between rows. Experimental design was a randomized complete block with !en treatments and four replications. Treatment subplots within blocks were 20-ft row segments. Treatment rows were alternated with guard rows. On 21 Jun, each subplot was inoculated with three ripe he1Ties displaying symptoms and signs of infection by~. acutatum, one beffY at either end of the subplot and one in the middle. All blossoms were removed until 7 Jul. Treatments were combinations of liming of application of fungicides (Benla!e SO WP, 8 ozJI 00 gal,+ Caplan SO WP, 3 lb/ I 00 gal) or of Gliocladium roseum(Peng and Sutton, Can. J. Plant Palhol., 13:247-2S7 , 199 1) and type of mulch (white-on-black plastic or straw). Guard rows were sprayed weekly with Benlate SO WP and Caplan SO WP, beginning on I Jul. Chemical fungicides or Q. roseum were applied lo runoff using a Solo backpack sprayer (Model No. 42S) with a flat-fan nozzle al approximately 30 psi pressure. Wetness duration and air temperature data for a postinfeclion disease-waining model (based on data of Wilson el al., Phytopathology 80: 111-116, 1990) were recorded hourly by a CR I 0 da!alogger and appropriate sensors (Campbell Scientific, Logan, UT). Ripe fruit were picked by hand, counted, weighed one to three times/wk, and be1Ties with symptoms of anthracnose rot were counted and weighed.