Page 14 - Vol.37-No.1 issue

CROP PROTECTION

SPOTLIGHT ON THRIPS

There are over 6,000 species of thrips “The nymphs and adults are often hid- identification is important because dif-
worldwide, including some which are den from view in flower buds or young ferent thrips require different solutions,”
predatory and many that survive on fun- folded leaves. Difficult to scout, it is im- says Simon.
gus alone. portant to deploy sticky traps for moni- Life Cycle
“While only around 1% of thrips spe- toring. It is critical to place traps close to
cies damage crops – they include some the crop as thrips are weak flyers.” Eggs are typically inserted into plant
of the most economically important Pest Host Range tissue. The early nymphal instars are
pests of global agriculture,” explains wingless but actively feed on crops,
Biobest’s IPM and Pollination Specialist while the prepupal and pupa stages are
Simon Foster. not active and non-feeding.
“They are serious pests due to their
wide distribution, polyphagous habits,
unusually high rate of reproduction, fast
development time and ability to quick-
ly develop resistance to pesticides. In
addition, a small number are plant virus
vectors, especially of the Tospoviruses.”

Male thrips develop from unfertilized
eggs – with the ratio of males to females
dependent upon factors including den-
sity and temperature. Its impressive
speed of development varies according
to temperature, crop type and resources
Simon Foster (IPM and Pollination available.
Specialist at Biobest) Solutions
Sign & Symptoms Successful thrips control strategies
Thrips damage crops through feed- consists of several parts. Remember that
ing and egg laying (oviposition). During prevention is better than cure.
feeding, the pests damage surface tis- To monitor the thrips, you can rely on
sues with their piercing-sucking mouth- Biobest’s Bug-Scan® in combination with
parts. the species-specific aggregation phero-
“On actively growing tissues feeding mone ThriPher (monitoring WFT).
causes distortion, reduced leaf area, Thrips species such as Frankliniella For biological control of thrips, you
stunting, excessive vegetative branch- occidentalis, Thrips tabaci and Thrips can introduce:
ing and even the death of new apical tis- palmi are global pests damaging a wide • Predatory bugs such as Orius-System;
sues,” explains Simon. “On fully grown range of crops including vegetables,
leaves, feeding can cause aesthetic berries, herbs and medicinal plants, or- • Predatory mites such as Amblyseius-
damage – while economic crop losses namentals and top fruit. System, Swirskii-System, Hypoaspis-
are particularly serious when they act as “Whatever the crop, prevention is key System en Montdorensis-System;
plant virus vectors. - plus a range of control methods with • Green lacewing Chrysopa-System;
differing modes of action - targeting dif- • Rove beetle Atheta-System;
ferent life stages,” explains Simon. • Nematodes such as Steinernema-
What does it look like System
To boost the population establishment
Thrips adults are small, slender insects of your beneficials, you can use the feed
with fringed wings - held unfolded at supplement Nutrimite™ in addition to
rest - and range in colour from pale yel- Swirskii-System.
low to almost black.
To discuss a thrips control strategy tai-
“Identification relies on microscopic lored to your crop, please contact your
features such as antennal segmentation local Biobest advisor.
and is often better left to an expert, but
Circle 15 on enquiry card
12 Vol. 37 No. 1