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Pests & Diseases
Two major pests of concern are the Caribbean fruit fly and Asian citrus psyllid. The latter causes citrus greening and has wreaked havoc with orange production throughout Florida, and has been found in a few orchards in California. Growers should also look out for purple scale and California red scale, nematodes, and red mites.

Common diseases include citrus canker, phytophthora molds, rust, scab, anthracnose, damping-off, greasy spot, leaf spot, felt fungus, stem-end rot, alternaria rot, various types of root rot and wood rot, as well as the crinkly leaf and exocortis viruses.

Storage & Packaging
Fruit is packed into bins in the field and transported to packinghouses for cleaning, grading, sizing and final packing. Lemons are coated with a fungicide and thin wax layer before curing in storage and later shipping.

Some growers cure loose fruit before grading and another round of curing. Early-picked lemons require about three weeks to attain best color but green lemons may be kept for four months or longer. More mature lemons may need less than a week to cure.

Degreening can be expedited by exposure to ethylene, but care must be taken as this can also promote decay. Packing lemons in thick, high-density polyethylene may minimize decay and allow storage for up to six months. Lemons can generally be kept for up to six months between 54 and 57°F with 90 to 95% relative humidity.

Tree yield varies by cultivar and location and is usually measured in field bins per acre with cartons for shipping. Lemons exported from Florida to Hawaii and Arizona are fumigated with methyl bromide to prevent Caribbean fruit fly infestations.

References: Purdue University, Texas A&M University, UC Davis Postharvest Technology Center, University of California Cooperative Extension.


Generally speaking, the percentage of defects shown on a timely government inspection certificate should not exceed the percentage of allowable defects, provided: (1) transportation conditions were normal; (2) the USDA or CFIA inspection was timely; and (3) the entire lot was inspected.

U.S. Grade Standards Days Since Shipment % of Defects Allowed Optimum Transit Temp. (°F)
12-7-3 5

There are no good arrival guidelines for this commodity specific to Canada; U.S. guidelines apply to shipments unless otherwise agreed by contract.

References: DRC, PACA, USDA.


The following defects are unique to lemons only:
• Any amount of mold from a decayed lemon affecting a sound lemon is scored as a defect
• Lemons are prone to internal defect and decline, usually found starting at the stylar end; any amount is scored as a serious damage defect
• Peteca is a deep, sharply defined pitting or sinking of the rind surface and scored as a defect when more than two spots or aggregating more than a quarter-inch in diameter.

Source: Tom Yawman, International Produce Training,

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This information is for your personal, noncommercial use only.