24 | The Blueberry News FloridaBlueberryGrowers.org

bug

of the

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Time to Watch for Chilli Thrips

CHILLI THRIPS (Scirtothrips

dorsalis Hood) are a significant

pest on southern highbush

blueberries in Florida. They

have piercing and sucking

mouthparts, used to feed

on young leaves and shoots,

causing leaf bronzing (Figures

1 and 2) and shoot dieback in

late spring and summer.

In Florida, most of the outbreaks in

blueberries have been recorded in June,

July and August on new growth, and can

begin shortly after the bushes are pruned.

During heavy infestations, the edges around

younger leaves and stems are eaten and leaf

curling develops (Figures 3 and 4). High

infestations of chilli thrips can reduce yield

the following season. In addition, plants with

feeding injury become more susceptible to

secondary infection and disease pathogens.

DESCRIPTION AND LIFE CYCLE

Chilli thrips are smaller than flower

thrips, less than 2 mm (0.08 inches) long

with dark fringed wings and dark spots

forming incomplete stripes across the back

of the abdomen (Figure 4). Female thrips

insert their eggs into blueberry tissues, and

the eggs hatch in about 6-8 days. Females

are capable of laying between 60-200 eggs

in their lifetime. Newly hatched larvae then

pass through two larval stages that typically

last for about six to eight days, during which

time they feed on blueberry tissues. They

then pass through a prepupal and a pupal

stage, during which they do not feed. Chilli

thrips complete their life cycle in 17 to 21

days under ideal conditions.

MANAGEMENT AND CONTROL

Management for chilli thrips includes

eliminating host plants in or near

production fields (including weeds that

support their growth and development),

applying recommended insecticides,

and using natural predators. Insecticides

that can be used to manage chilli

thrips include Delegate® (Spinetoram),

Assail® (Acetamiprid), and Sivanto®

(Flupyradifurone). Malathion and Sevin®

(Carbaryl) can also be used, as well as

Entrust® in organic production. Delegate® is

typically a very effective tool for control, and

has the added benefit of conserving natural

enemies that regulate the thrips population,

such as Orius insidiosus (minute pirate

bug) and Geocoris spp. Be sure to follow all

label instructions and rotate insecticides

from different classes to minimize the

development of resistance.

Figure 1. Chilli thrip damage.

photo credit UF MREC

Figure 4. Adult chilli thrip.

photo credit UF MREC

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CREDIT

by DOUG PHILLIPS, Blueberry Extension

Coordinator, University

of Florida/IFAS