Pear Disease Spray

The pear orchard demands constant vigilance against a number of pests and disease organisms. While ethnic practices go a long way in preventing some diseases, like fire blight, once a disease pathogen has taken hold, using bactericides, antibiotics and fungicides is in order.


The two diseases which cause the most important damage to pear trees are fire blight, a bacterial disease, and pear scab, caused by a fungus (Venturia pirina). While the two diseases are serious, fire blight is the more destructive of the two. The bacterium (Erwinia amylovora) spreads into your pear tree by pest activity and by polluted soil that is splashed onto the pear tree during irrigation or heavy rains. Pear scab, on the other hand, is identified by yellow spots on the tree’s foliage. If not prevented, the infection spreads to other areas of the tree, and whether or not it affects the blossom comes, the blossoms will drop.

Types of Spray Treatments

Fire blight typically strikes the pear tree’s blossoms first. Disease sprays applied in the proper time help stop or contain the illness. The University of California Integrated Pest Management Program recommends streptomycin spray since the best treatment for pear fire blight, though terramycin sprays in addition to copper sprays and Bordeaux mixture may be used instead. Preventing pear scab calls for a careful adherence to your spray schedule and includes the usage of Bordeaux mixtures, fixed copper spray, neem oil or copper soaps.

Disease Spray Timing

Wet, cloudy or foggy weather in the days leading up to blossom boost the development of the bacteria which causes fire blight. Streptomycin sprays to inhibit the development are therefore best applied during wet weather, when the flowers are in blossom and temperatures are between 60 to 75 degrees Fahrenheit. You need to reapply the product for optimum safety, so comply with the schedule on the tag. When treating the pear tree for pear scab, use copper or Bordeaux sprays just between bud swell and blossom. Applying these products after this period may result in burning the pears’ skin. If rain is in the prediction, reapply the product when the leaves start to emerge. Again, the schedule listed on the item’s tag is the very best guide.


Pesticide sprays work in tandem with disease sprays to control fire blight on pear trees. Aphids and pear psylla, a tiny cicadalike insect, assist in the spread of the bacteria that causes the disease. Using a dormant oil spray in the fall is the best approach to see to the pear tree for insects, especially the pear psylla, which tends to overwinter on the tree. Whether spraying the pear tree for disease or pests, products must be applied heavily enough to ensure comprehensive coverage.

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