Citrus tree owners who have noticed that immature fruit is forming a carpet under their trees may have to take up arms against Postbloom Fruit Drop (PFD) In a recent Department of Agriculture and Fisheries bulletin, Senior Plant Protection Officer Terrylyn Thompson discussed the disease and its causes.

PFD results when citrus blossoms are infected by a virulent strain of fungus.

Normally citrus flowers form in late winter and early spring and there are always more of them than the eventual fruit.

Depending on climate factors, especially heat and moisture, less than one percent of the flowers set fruit and the rest fall off.

However the presence of Colletotrichum gloeosporiodes -- the fungus that causes PFD -- results in even more flower loss.

Infected trees show peach and orange-coloured water soaked patches on their petals which usually do not form until the open flower stage.

These patches contain fungal spores and expand rapidly in humid wet conditions until all the petal tissue is infected -- a stage often called blossom blight.

These blighted petals remain firmly attached to the twig and entire flower clusters may be attacked by the fungus. After flowering, the tiny fruits fall off the tree leaving the floral parts or "buttons'' attached to the tree.

Under normal conditions, these buttons are shed along with the fruit.

The fungus thrives and causes appreciable damage when periods of prolonged wetness coincide with blossom peaks, usually between February and April.

Ms Thompson said trees should be sprayed when flowers predominate and, if applied in a timely manner, the fungicide benomyl protects the blossoms from PFD.

The disease was first discovered in Belize in 1956 and has since spread to all areas where citrus trees grow.

Local estimates for 1995 put citrus losses as high as 36.6 percent for grapefruits and 36 percent for oranges.

In other news from the bulletin, Ms Thompson also warned about a serious threat to cedars.

The Juniper Aphid, or Cinara tujafilina , is a sucking pest which poses a danger to young cedar trees, particularly those less than four or five years old.

The bug is large and a brown/grey colour and can be found feeding on the tips of cedars.

Populations of this pest begin to increase in March and April and serious damage can be done which can be identified by the trees' tips turning red and dying.

This can be generally tolerated by most young trees unless a severely dry summer follows the time when they are damaged by the bug.

The best way to control the pest is to closely monitor cedar trees and treat them with an insecticide when required, said Ms Thompson.

She said tree owners should examine the trunk and branches carefully as the aphids can blend in well with the bark.

If ant trails up the tree are noticed, this is a good sign that a sucking pest, such as Juniper Aphids are present as the ants are feeding on honeydew produced by the sucking.

Ms Thompson recommended insecticidal soap or horticultural oil be applied in a bid to control the pest.