Figure 1. Uneven bud break is often associated with trees grown in climates with milder winters.
Uneven bud break is affecting some of the apple varieties at Meigs (Fig. 1). This is usually associated with apples that grow in areas with mild winters, like the one we just had. Apple trees in warmer climates often demonstrate uneven bud breaking and bloom times. With some trees exhibiting everything from silver tip to pink, the question must be asked: To spray, or not to spray? This is quickly followed by what do you decide to spray?
My vote is to spray. In examining leaf litter, pseudothecia are formed and forming. Although this is early in the season, spores will infect bud scales just like they infect leaves, and in this case, may infect both at the same time! There may be only 5% of the pseudothecia producing mature ascospores, but infection can and will occur. And each one of those ascospores can produce a lesion with almost 100,000 more conidia (asexual spores). A few ounces of prevention now will yield tons of cure later!
Based upon the presence of so many shoots at pink, copper is not an option. With future rains in the forecast, captozeb (captan+mancozeb) is probably your best bet, until more green tissue is there. Other options, if the weather stays cool, include Vanguard and Scala. Saving your DMI application (Inspire, Indar, Rally, etc.), strobilurin (Flint, Sovran), premix (Merivon, Luna Sensation, Pristine), or SDHI (Fontelis, Aprovia) until more green tissue is present will probably be a more strategic use for them.
Figure 2. Mummies serve as a point of infection for many of the summer rots. Their removal, although painful and tedious, does reduce overwintering inoculum, and improve disease control.
Also, for those of you with mummies (Fig. 2)—with all the bitter rot, white rot and black rot last season, remove everything you can. This is easier said than done. Some cultivars seem to be worse than others (Honeycrisp, Fuji). We will try to do some experiments on our Honeycrisp with and without mummies, to see what impact mummy removal has. Also, check out page 77 of the Midwest Fruit Pest Management Guide. There is some great information on chemical thinning, and how to avoid those pygmy apples that turn into mummies. As always, forewarned is forearmed!