Rots and Spot, Fruits and Vegetables
1. Cedar-apple and cedar-hawthorne rust are similar but different diseases for which it is too
late to apply a fungicide. Cool, moist conditions this spring have increased infections on
susceptible apple, crabapple and Hawthorne trees. Both diseases cause yellow spots on upper
leaf surfaces and raised orangish-postules on leaf undersides. Both require two hosts to complete
their life cycle, with one host being Juniper such as cedar trees. While it would take a number of
years of severe infection to harm tress, infected leaves may drop resulting in unsightly trees and
poor fruit production in apples. Repeated yearly infections can weaken trees and lead to other
issues.
The best control of rust is selecting resistant trees. On susceptible trees with a history of
infection, fungicides need to be applied in early spring just as buds are opening and applications
repeated two or three times.
http://www.ianrpubs.unl.edu/epublic/live/g1907/build/g1907.pdf. Nebraska Extension
2. Apple & pear scab - Apple scab is infecting apples and crabapples. This fungal disease is
favored by wet, humid weather occurring from late April through June. The disease decreases
yields, reduces fruit quality, defoliates trees, and reduces tree vigor. The fungus can overwinter
on or near trees so we often see this disease before cedar apple rust. Leaf lesions of apple scab
are usually olive colored and turn brown.
Pear scab is very similar to apple scab, including leaf and fruit lesions, and is caused by a closely
related fungus.
As with rust, planting resistant cultivars is the best means of control. Fungicides can be applied,
but applications need to begin in early spring to reduce infections.
http://www.ianrpubs.unl.edu/epublic/live/g1922/build/g1922.pdf Nebraska Extension
http://www.caf.wvu.edu/kearneysville/disease_descriptions/ompearsc.html West Virginia
University
3. Fruit drop - Homeowners are often concerned when their fruit trees begin dropping fruits, but
this is actually a pretty common occurrence. Fruit drop can happen for several reasons.

Lack of pollination - The first occurrence of fruit drop happens right after blooming and
petal fall when the new fruits are still tiny, approximately pea-sized. Fruits that did not
pollinate properly fall from the tree. Cold or wet conditions during flowering reduces
pollination due to a lack of bee activity. Cold temperatures during flowering may kill
flowers and result in fruit drop. A lack of pollinators can also be a problem.

Fruit load - A second round of fruit drop often occurs in early to mid-summer when fruits
are about marble sized. This condition is often called June drop and is thought to occur
due to competition between fruits for resources - water, nutrients and
carbohydrates. Trees often set many more fruits then they have the ability to bring to
maturity. Trees are limited by their vigor and the amount of leaves present to
photosynthesize and create carbohydrates for fruit development. Fruit thinning by the
orchardist can minimize June fruit drop. Apples and pears are particularly prone to June
drop, but it is less common in cherries. Hot, dry weather in late spring or early summer
contributes to June drop. Fruit drop at this time allows the remaining fruits to develop
properly.

Insect or disease problems - Fruits infected with diseases or insects often fall from the
tree early. Check falling fruits for signs of common diseases or cut them open to look for
wormy insects like immature codling moth or plum curculio larvae.
Despite natural fruit drop, trees may still be in need of hand thinning to 1) prevent branch
breakage of overloaded branches, 2) allow remaining fruit to develop good size, and 3) allow
good fruit bud development for next year and prevent trees from developing an every-other-year
bearing cycle. After thinning, apples should be spaced 1 fruit per every 8-10 inches of branch.
Pears, plum, apricot and peaches should be spaced 1 fruit per 6-8 inches of branch. Apples and
pears often bear fruits in clusters and should be thinned to allow only one fruit per cluster.
homeorchard.ucdavis.edu/8047.pdf, University of California
4. Broccoli harvest will begin soon. Head development is beginning for early spring plantings.
Broccoli is usually ready to harvest 65-70 days after transplanting. The heads of broccoli are
really flower buds. These must be harvested before the flowers open or show yellow. Mature
heads measure 3-10 inches across. Cut the main stem about 6 inches below the main head. After
the main head is harvested, lateral heads may develop from the leaf axil lower down the
stem. Although they will be smaller than the main head, they can also be harvested when the
flowers have developed but are still dark green and closed.
Early head development, or bolting, may occur before plants have had a chance to develop a
good size if the plants are exposed to heat stress or if over-mature transplants were used. If
bolting occurs broccoli heads should be harvested small, then the plants should be removed from
the garden. There is no way to "slow the plants down" or make the small heads develop more
size before they become over-mature.
http://www.extension.umn.edu/garden/yard-garden/vegetables/growing-broccoli-cabbage-andcauliflower-in-minnesota/, University of Minnesota Extension
5. Blossom end rot is a common problem of tomatoes, but also affects peppers, eggplant, squash
and watermelon. It appears as a flat, dry, sunken, brown rot on the blossom end of fruits caused
by a calcium deficiency in the fruit. In Nebraska, rarely is there a lack of calcium in the soil.
Blossom end rot occurs when plants cannot pull calcium up quickly enough for developing
tissues. Calcium must be dissolved in water to move within a plant, so dry soils can increase the
problem.
Drought stress, low daytime humidity, high temperatures, and rapid vine growth favor blossom
end rot. Applying calcium to the soil or to the plant is not beneficial. Instead, maintain a
consistently moist but not saturated soil; use organic mulch near the base of plants; and avoid
excess nitrogen fertilization with ammoniacal nitrogen sources.
Often the first ripe fruits are affected. Remove them and later ripening fruits will usually be
normal.
http://ohioline.osu.edu/hyg-fact/3000/3117, html Ohio State University
https://www.youtube.com/watch?v=N70yDwYEyYs, Nebraska Extension
Robert Tigner
Nebraska Extension Educator-Agriculture
Red Willow County Extension
1400 West 5th Street
McCook, NE 69001
[email protected]
308-345-3390