Title : Citrus Thrips
Visit Count : 2246 Time(s)
Upload Date : 4/11/2016 - 2 Year(s) ago
Category : citrus
Monday, April 11, 2016
Visit Count : 2246 Time(s)
Upload Date : 4/11/2016 - 2 Year(s) ago
Category : citrus
Scientific Name: Scirtothrips citri

Adult citrus thrips are small, orange-yellow insects with fringed wings. During spring and summer, females lay about 25 eggs in new leaf tissue, young fruit, or green twigs; in fall, overwintering eggs are laid mostly in the last growth flush of the season. Overwintered eggs hatch in March about the time of the new spring growth. First-instar larvae are very small, whereas second-instar larvae are about the size of adults, spindle-shaped, and wingless. They feed actively on tender leaves and fruit, especially under the sepals of young fruit. Third- and fourth-instar (propupa and pupa) thrips do not feed and complete development on the ground or in the crevices of trees. When adults emerge, they move actively around the tree foliage.
Citrus thrips do not develop below 14°C. They can produce up to eight generations during the year if the weather is favorable.
When monitoring citrus thrips, you must be able to distinguish them from flower thrips, which feed on flower parts but do not damage citrus. Shortly after petal fall, immature flower thrips can be seen moving around young fruit, but they soon pupate and adults disperse to other plants, consequently they are only concentrated in citrus orchards for a short period in spring.
Citrus thrips is of greatest economic importance on San Joaquin navel oranges, desert citrus, and coastal lemons. On fruit, the citrus thrips punctures epidermal cells, leaving scabby, grayish or silvery scars on the rind. Second-instar larvae do the most damage because they feed mainly under the sepals of young fruit and are larger than first instars. As fruit grow, damaged rind tissue moves outward from beneath the sepals as a conspicuous ring of scarred tissue. Fruit are most susceptible to scarring from shortly after petal fall until they are about 1.5 inch (3.7 cm) in diameter. Thrips damage is higher on fruit located on the outside canopy where fruit is also susceptible to wind damage and sunburn.
Check young fruit for immature thrips and monitor the undersurface of inside foliage for predaceous mites. Monitor from petal fall until fruit is greater than 1.5 inches in diameter. For oranges, the monitoring time is about 6 to 8 weeks in spring. For lemons, monitor June through October.
http://www.ipm.ucdavis.edu
In This Category :
All rights reserved for Cooperative Companies Union of Mazandaran Gardeners , Copy Right 2015 Total Visits count :
278/167
Past 10 days report