Insetti e Acari: Quarantena e Qualit

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Acari Mesostigmata
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Key for the main ACARI orders and suborders

• 1-4 pairs of dorso-lateral or dorso-ventral
  stigmata, posterior to the coxae
  II Parasitiformes 2
• - stigmata not visible posteriorly to the coxae
  II Acariformes 3
• 2. Palptarsus without claws stigmata back to
  coxae IV or latero-dorsal to the region between
  coxae II-III presence of stigmatic plate
  hypostome transformed in a piercing organ
  provided with recurved teeth Ixodida
• - Palptarsus with a terminal, subterminal, or
  basal claw with 1-2 pairs of stigmata in the
  region between coxae II-III and III-IV, commonly
  ventro-lateral peritreme usually present
  tritosternum generally present Mesostigmata
• 3. 2 segmented palps, stigmata absent Astigmata
• sometimes minute palps but with 3-5 segments
  stigmata present or absent 4
• 4. stylet-like or hooked chelicerae, raraly
  chelate Prostigmata
• chelicerae tipically chelate Oribatida

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MESOSTIGMATA
Mainly predators, free-living in the soil and in
decaying organic matter. Some species are adapted
to the parassitism on Vertebrates and
Invertebrates. Size length between 0.2 and 2 mm.
Dermanyssus gallinae
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MESOSTIGMATA
Usually the digitus mobilis and fixus can develop
a chela. Dermanyssina and Parasitina males have
a spermatodactyl on the digitus mobilis. The
female is often provided with an accessory pore
for sperm insemination between the III and IV
pair of legs.
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MESOSTIGMATA Laelapidae Hypoaspis aculeifer
Female reddish, 600-940 µm long, male 520-540 µm
long. Edaphic mite, free-living in the soil,
largely spread and easy to rear. It lives mainly
in the most superficial layers of the soil, but
also in storehouses. Largely polyphagous,
predators of mites, spring-tail larvae, other
insects and nematodes.
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MESOSTIGMATA Laelapidae Hypoaspis aculeifer
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MESOSTIGMATA Laelapidae Hypoaspis aculeifer
The female lays eggs for a long time as a
consequence of its longevity (from 48 to 100 days
at 25C).
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MESOSTIGMATA Laelapidae Hypoaspis aculeifer
It can survive also for 5 months without its
elective prey. Arrhenotoky (partenogenesis), the
eggs are laid in the soil crevices and on organic
matter in groups of 15-50 units which can be the
result of more gravid females.
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MESOSTIGMATA Laelapidae Hypoaspis aculeifer
MESOSTIGMATA Laelapidae Hypoaspis aculeifer
Tube of 1 liter containing 10.000 or 25.000
mites.
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MESOSTIGMATA Phytoseiidae
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MESOSTIGMATA Phytoseiidae
Mean length 500 µm ? smaller. Shape oval or
pear-shaped, often subpentagonal, dorso-ventrally
flattened ? pear-shaped. Generally yellowish or
pale yellow, sometimes pinkish, often the colour
depends on the ingested food for 24-30 hours
integument smooth and glossy.
(from Hoy, 2011)
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PHYTOSEIIDAE
Gnathosoma with chelate chelicerae ? provided
with the spermatodactyle 5-segmented palps rich
in sensilla. Leg I with a sensorial function and
helping to capture the prey.
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PHYTOSEIIDAE
Large dorsal plate with, at most, 20 pairs of
setae, a variable number of pores and integument
more or less smooth or reticulated.
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PHYTOSEIIDAE
Three ventral plates, accessory pores for
insemination ( sperm induction pores), a genital
pore, stigmata and peritremes.
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PHYTOSEIIDAE
Males guarding quiescent Dn. Postembrionic
development E, L, Pn, Dn. Eggs are laid singly
or in small groups on the undersurface of the
leaves, close to the main veins. Female-biased
sex ratio commonly about 2.5 females to 1 male.
Phytoseiulus persimilis
Tetranychus urticae
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PHYTOSEIIDAE
Egg fertilization (podospermy insemination) and
parthenogenesis (pseudoarrhenotocky).
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PHYTOSEIIDAE
Larvae of some species usually do not
feed. Overwintering mated ?? in sheltered
places scarcely resistant to low temperature.
Diapause induced by short day-light temperature
seems to have a secondary role. Role of feeding
pygments (e.g. ß-carotene). Considerable
adaptations to the variable ecological
conditions living in the soil, on numerous plant
species and sometimes also on stored food.
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PHYTOSEIIDAE
Biologic parameters (fertility, longevity,
development rate, etc.) depend on the phytoseiid
species, prey species, population density of the
prey, environmental conditions (climate,
alternative food). Usually males develop more
quickly than females.
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PHYTOSEIIDAE
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PHYTOSEIIDAE
A ? of A. andersoni (Chant) lays 1.3-2 eggs per
day in about 99 days, while a ? of P. persimilis
Athias-Henriot lays an average of 2.4 eggs per
day in about 30 days.
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PHYTOSEIIDAE
Development rate is faster than that of the
phytophagous mites, in the same conditions of
humidity and temperature. Fertility
lower than that of their preys, especially
tetranychids. Longevity is very close between
preys and predators.
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PHYTOSEIIDAE
They are usually on the undersurface of the leaf.
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PHYTOSEIIDAE

• They are able to find the prey thanks to
• kairomones (volatiles and non volatiles) emitted
  by the prey and contained in the silk, exuviae,
  eggs and faecis.
• Synthetic volatiles produced by spider mite
  infested plants

Tetranychus urticae (adult) (egg) (web)
Phytoseiulus persimilis
Faecis of Tetranychus urticae
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PHYTOSEIIDAE trophic regime

• Obligatory predators
• Phytoseiulus persimilis,
• Metaseiulus occidentalis
• (unable to develop or reproduce on alternative
  foods such as pollen or honey case of
  cannibalism or intraguild predation)
• Generalist predators (Typhlodromus pyri)
• Generalist and facultative predators
• oligophagous
• polyphagous (Typhlodromus exhilaratus)

Two categories with respect to the prey
density - at low prey density - at high prey
density (monophagous or oligophagous). The
predators prefer to feed on juveniles and eggs.
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PHYTOSEIIDAE species applied in augmentative
biological control
Phytoseiid species Target/s
Phytoseiulus persimilis Tetranychus urticae
Metaseiulus occidentalis Tetranychus spp.
Amblyseius cucumeris Thrips and spider mites, cyclamen and broad mites in greenhouses
Neoseiulus degenerans Thrips and spider mites
Amblyseius californicus Tetranychus spp.
Neoseiulus barkeri Thrips larvae in greenhouses
Amblyseius swirskii Whiteflies, thrips, and other small insects in greenhouses
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PHYTOSEIIDAE side effects of pesticides

• Produced by non selective aa.ii. (broad spectrum
  chemicals).
• Insecticides pyrethroids (deltamethrin,
  cypermethrin, etc.), organ-fosphorates and
  carbammates at broad spectrum.
• Fungicides (dithiocarbammates mancozeb, maneb,
  metiram, propineb, zineb, others against
  Plasmopara) toxicity is usually inferior than
  that of the main insecticides, but they are
  applied repeteadly, especially with small
  phytoseiid populations.
• It can be distinguished
• direct effects (mortality, fertility reduction)
  and
• indirect effects (disappearance of alternative
  preys).

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Toxicity and persistance of some pesticides on
Phytoseiulus persimilis
insecticides
fungicides
acaricides
These aa.ii. cause a reduction of the control
capacity of the pests A lt 25 B 25-50 C
50-75 D gt 75 - value non available a.i. with
acaricides proprierties, too. values also for
bifenthrin, cyfluthrin, cypermethrin,
deltamethrin, fenpropathrin, permethrin
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PHYTOSEIIDAE

• Genetic improvements
• Selection of strains
• a) resistent to pesticides (e.g., Metaseiulus
  occidentalis resistant to abamectin, OPs,
  carbaryl, sulfur),
• b) with particular prey preference,
• c) inability to diapause under greenhouse
  conditions during winter,
• d) for improved high-temperature tolerance
• production of transgenic predators (maternal
  microinjection)

• Techniques for predator release
• Sheltering places
• Cane method
• Direct release
• Release

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PHYTOSEIIDAE

• Cane method release
• Sprouted canes of 2 years with 5-10 overwintering
  ??/node

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Phytoseiulus persimilis

• Obligatory predator of Tetranychus urticae
  (acaricide on legs).
• Considerably active and with a huge ability in
  searching for the prey.
• Cycle span
• 15C 25 days
• 20C 9 days
• 25C 5 days

Mobile individuals brilliant orange Egg
orange-pink
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Phytoseiulus persimilis
Tab 10 Influence of humidity and temperature on
the development of the eggs in P. persimilis.
hatching
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Phytoseiulus persimilis
Development phase and fertility are longer/higher
than those of the prey at 15-18C, 55-95 R.H.
Fertility 75 eggs/female (17-26C).
Optimum rate of population increase is at 32C
warm and damp climate maximum predatory activity
is carried out at 65-75 di R.H. Tetranychids
optimum rate of population increase is at 35C
warm and less damp climate. Required water. It
doesnt reproduce if it does not fed on its
prey. Cannibalism. Residual side effects of
pyrethroids and dimethoate.
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Phytoseiulus persimilis
Bio-firm item active instars mixed with
dispersing material (wet vermiculite). Applied in
inundative programmes. Take care of - release
mites as soon as you can - storing at 8-10C at
most for 24 h temperature must be gt than 4C -
do not expose the box to the sun light or warming
directly - rotate horizontally the closed
container before application - release should be
done placing horizontally the container, having
care that the highest predator concentration will
be released in the most infested places.
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• Doses depend on
• - infestation level - average number of
  phytophagous mite/leaf, number of infesting
  clusters. Preypredator ratio ? 151 e 301
• - sensitivity of the crop
• environmental conditions high temperature and
  dried climate favour T. urticae, therefore a
  higher dose of predators is needed and the
  release should be done at a lower threshold
• - vegetative stage of the crop contact between
  plants.