Apply the third spray about 10 to 14 days after the first.Apply the second spray about 5 to 7 days later.Apply the first spray when one-third of buds reach the stage of delayed green tip.This corresponds with the period of greatest discharge of ascospores. The period from delayed green tip to petal fall is most important in preventing infection. Principles of control are very similar to those for apple scab.Ĭontrol is based on a protectant spray program, supplemented by post-infection and autumn eradicant sprays. Infection periods (the time that leaves or fruit must remain wet for infection to occur) of pear scab are similar to those described for apple scab, though few detailed studies have been carried out to confirm this. Though overwintering as ascospores in dead leaves under trees is still the most important source of primary inoculum. These shoot infections can provide the fungus with another means of overwintering. The main difference is that, under Victorian conditions, shoot infections on pears are more common than on apples.

The disease cycle of pear scab is similar to apple scab. They appear as small oval blisters on the affected shoot. Twig infections, on the other hand, are more common than in apple scab.Leaf infections, which are less common than in apple scab, frequently occur on the underside of leaves (see Figure 4).As with apple scab, infections immediately before harvest may produce very small black spots that develop on fruit during storage (storage scab).Early infections cause large spots that distort the fruit (see Figure 3), while later infections cause smaller, more superficial spotting.

Fruit infections appear as olive-green to black spots (see Figures 1 and 2).The symptoms of pear scab are very similar to those of apple scab: But, though the diseases are similar, infection can't cross between them.

The fungus is closely related to apple scab. The disease is found worldwide, wherever pears are grown. Control of the disease depends mainly on costly spraying programs. It can cause serious crop loss, especially in wet seasons when control measures are inadequate. It's caused by the fungus Venturia pirina and infects: Pear scab, or black spot, is the most serious and widespread fungal disease of pears.

Pear blight treatment