PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
Management (IPM)
Are you a commercial grower or home gardener?
1.Obtain/prepare a plan that fits your situation.
Obtain leaflets on gladiolus thrips control for your
local area. See IPM program for WFT as an example
(see page 139).
2.Crop, region. Recognize variations.
3.Identification of pest must be confirmed. Consult
a diagnostic service if necessary (page xiv).
Commercial growers must confirm that the problem is
thrips and that the thrips present is gladiolus thrips.
4.Monitor pest and/or damage and record results as
recommended (page 39). Use blue sticky traps to
monitor thrips and any beneficials in the crop or
introduced to the crop before deciding treatment
(page 139). Indicator plants can be used to detect
new arrivals.
5.Threshold. How much damage can you accept?
Have any thresholds been established? If so, what are
they, eg economic, aesthetic?
6.Action/Control. Take appropriate action when
any threshold is reached. Remember thrips need to be
managed rather than controlled.
7.Evaluation. Review IPM program to see how well
it worked. Recommend improvements if required.
Continued monitoring is usually necessary.
Control methods
Cultural methods.
For new plantings select land as far away as
possible from old plantings and volunteer plants.
Avoid continuous cropping if practical.
Commercial growers whose properties are
isolated from areas in which gladioli or other
host plants are growing, may make a break in
planting, so that for a period of several months
there is no foliage on which thrips can develop.
Adult thrips do not fly readily. Where there is a
dominant prevailing wind, early-blooming
varieties can be planted in beds furthest downwind.
Later-blooming crops can then be planted
upwind from older infested crops.
Gladiolus thrips is favoured by hot dry weather,
frequent use of overhead sprinklers or hosing of
plants will retard development of thrips but may
damage flowers. Ensure satisfactory drainage.
Sanitation.
Remove and dispose of crop residues.
Dispose of all trash (old plants, flowers, leaves,
growing media, etc) and old unsaleable plants
which could harbour thrips, daily.
Pull up and destroy volunteer gladioli and other
host pants growing around production areas
before planting the main crop.
Place old blooms infested with thrips in a black
plastic bag, seal immediately and leave in sun to
solarise (heat up) for at least 3 days to kill thrips.
Keep greenhouses and surrounding facilities
clean, neat and orderly.
Fallow greenhouses between crops (page 139).
Do not move from infested to ‘clean’ areas.
Avoid wearing pale coloured clothing such as
white, yellow or blue which attract thrips.
Fig. 98. Gladiolus thrips (Thrips simplex). Left: Injury to gladiolus flowers and foliage.
PhotoCIT, Canberra (P.W.Unger). Right upper: Corm showing injured area and killed rootlets around
basal plate. Right lower: Uninjured corm. Photos NSW Dept of Industry and Investment.
134 Insects and allied pests - Thysanoptera (Thrips)