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What to Look For: Signs of the Insect & Disease

The Asian Citrus Psyllid - Diaphorina Citri Kuwayama

It can take years for symptoms of the disease to appear, meaning inspection for the psyllid is our best line of defense.

Use a magnifying glass or hand lens.
Inspect when watering, pruning or tending trees.
Pay close attention during times of leaf growth, or "flushing."

What does the Asian Citrus Psyllid look like?

The psyllids develop from an egg through five nymphal stages that look similar, but increase in size after each molt. Due to the small size – even of adult psyllids – inspection is done more easily with a magnifying glass or hand lens.

Eggs are bright yellow-orange and almond shaped, and appear in groups on the newest, most tender, unfolded leaves.

Image of Psyllid Nymphs, which are young Psyllids Nymphs are dull orange, have red eyes and produce waxy tubules that direct honeydew away from their bodies. They can be difficult to see because they are small and flatten themselves
against twigs
and leaves.

Image of the sooty mold that Nymphs produce on hlb infected citrus leaves Nymphs are slow, do not fly or jump, unlike their adult counterparts, and the honeydew they produce causes sooty mold to grow.

Image of an Adult Citrus Psyllid insect Adults are small (3-4 mm or 1/8-1/6 inch), brownish insects that are similar in size to an aphid. They feed with their heads down, almost touching the surface of the leaf.

Because of the shape of their heads, their bodies are lifted to approximately a 45-degree angle.

Psyllid Inspection 101

When?
Image of a citrus tree during new growth, also called 'flushing' Inspection should be done on a regular basis and especially during periods of active plant growth or “flushing.” Eggs and nymphs are only present during flushing and, while adults can be present year-round, they are easier to spot on the tender leaves of spring and fall flush.

Where?
Image of new tree growth that is infested with the Psyllid, you should look
for the Psyllid on new tree growths The psyllid adults and nymphs are typically found on new shoots, along with eggs, which are often nestled in crevices of unfolded leaves.

How Often?
Inspect trees monthly and whenever watering, spraying, pruning or tending trees. It’s especially important to inspect during active growth, or flushing.

How can I tell if my tree has HLB?

Detection of HLB can be difficult, as the symptoms may not show up for more than a year and the leaf symptoms can resemble other diseases and nutritional deficiencies.

Image of the asymmetrical patterns on leaves of infected trees, which is a typical blotchy mottle on HLB infected leaves However, HLB leaf symptoms are unique in that the yellow mottling caused by HLB is not the same on both sides of the leaf.

Image of small and premature fruit that
has been affected by the Asian Citrus Psyllid Later symptoms of HLB-infected trees include yellow shoots, lopsided small fruit, and premature and excessive fruit drop. As HLB progresses, leaves and whole branches fall off the tree and eventually the entire tree dies.