Diseases and Management of Crops under Protected Cultivation
Diseases and Management of Crops under Protected Cultivation
Diseases and Management of Crops under Protected Cultivation
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(<strong>Diseases</strong> <strong>and</strong> <strong>Management</strong> <strong>of</strong> <strong>Crops</strong> <strong>under</strong> <strong>Protected</strong> <strong>Cultivation</strong>)<br />
translucent at first but become orange after feeding. Adult females are slightly larger than males. It<br />
is host specific preferring the eggs <strong>and</strong> young stages <strong>of</strong> its prey. An adult female can consume ten<br />
to twenty spidermite eggs per day. Its development takes about 5 days at 30°C, The female lays<br />
2–6 eggs per day <strong>and</strong> during life cycle it lays about 106–108 eggs. The life span <strong>of</strong> the predator<br />
is 20–25 days. This mite requires a relative humidity <strong>of</strong> greater than 60% in order to survive<br />
especially in egg stage This fast development is an important factor in its success as a predator.<br />
The initial ratio <strong>of</strong> pest to predator decides the outcome <strong>of</strong> a control programme, therefore the<br />
initial dose <strong>of</strong> the predator must be sufficient to achieve control before the damage is done, how<br />
ever the control can be unsatisfactory at very high temperatures <strong>and</strong> low humidities, great thing<br />
about this species is that it dies after the spidermite population is gone, cannibalizing on each<br />
other.<br />
Release Methodology<br />
Introduction<br />
• Turn <strong>and</strong> shake the bottle gently before use<br />
• Sprinkle material on leaves or pour into application boxes<br />
• In low crops, it is possible to distribute predatory mite packing mechanically by means <strong>of</strong><br />
the mite blower<br />
Environmental conditions<br />
Relative humidity should be greater than 75% <strong>and</strong> the temperature above 20°C/68°F for<br />
some hours <strong>of</strong> the day. Phytoseiulus persimilis does not enter diapause.<br />
Storage <strong>and</strong> h<strong>and</strong>ling<br />
• storage after receipt: 1-2 days<br />
• storage temperature: 8-10°C/47-50°F<br />
• in the dark (bottle horizontally)<br />
Appearance<br />
Adults: bright red, very active, spherical, st<strong>and</strong>s high on its legs<br />
Eggs: oblong, first pink <strong>and</strong> transparant, later on darker, twice as big as spidermite eggs<br />
Larvae/nymphs: pale to light red<br />
Mode <strong>of</strong> action<br />
Adult predatory mites <strong>and</strong> nymphs search actively for their prey <strong>and</strong> suck them dry.<br />
Visual effect<br />
Adult red spidermites that have been eaten change colour from brown to black (in tomato)<br />
<strong>and</strong> can be identified as tiny black dots on the leaves. This should not be confused with living,<br />
light-brown to dark-red spidermites.<br />
For hotspots<br />
Release Rates<br />
Phytoseiulus persimilis rate interval (days) frequency remark<br />
Preventive 2/m² 21 - -<br />
Curative light 6/m² 7 1-2x -<br />
Curative heavy 20-<br />
50/m²<br />
7 2x introduce in infested<br />
areas only<br />
- 70 -
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