University of Illinois Extension
Bruce Spangeberg

These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.

Stateline Yard & Garden

Preventing Annual Apple and Tomato Problems

June 4, 1998

When growing vegetable or fruit crops, there are some problems to be expected about every year. Last week's column discussed cucumber beetle. This week looks at apple maggot and blossom end rot. Both are common problems that are managed by preventative practices before they become a problem on the plant.

Harvesting apples from the backyard orchard is a seasonal highlight for many gardeners. It can be discouraging, however, to pick poor quality fruit. A common problem is bumpy apples with streaks of brown inside. This is the work of the apple maggot. Adults are small flies that typically start laying eggs in early July and continue through August.

Adult apple maggots will lay eggs on the skin of the apple, damaging the fruit even if the eggs don't hatch. Larva tunnel into the apple, and a soft rot will follow, causing the brown trails in the flesh. The larva is small and rarely seen, not to be confused with the larger "worm in the apple" associated with another insect called the codling moth.

There is plenty of time to prevent damage, as apple maggot typically is out in July and August. One control option is to continue applying insecticides that are included in multipurpose fruit sprays at two-week intervals throughout July and August. Another option that does not require insecticides is to use "sticky traps" to catch the adult fly. Red spheres coated with adhesive and hung in trees can be used to "trap-out" apple maggots from backyard orchards. This is only for apple maggot control however, not other insect pests or diseases.

Blossom end rot of tomato occurs each summer with varying severity. It's typically noticed as you pick a ripening tomato and find the underside black and rotten. Blossom end rot is due to a lack of calcium caused by fluctuating soil moisture as the fruit develops.

Mulching the soil and watering as needed during dry spells that may occur should keep the problem in check. Monitor the soil conditions closely as we advance into summer and fruit is developing on the tomato plants.

Take action over the coming weeks so these two annual problems don't ruin your harvest later this season.


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