Entomology

1. PHYTOPHAGOUSMITE& THEIRBIOLOGICALCOTROL
Characteristics of phytophagous mite:-
Mites belong to order Acarina.
Mites distinguished from their insect relatives by the two body region (cephalothorax and
abdomen in some orders, these two parts are fused), sucking mouthparts, lack of
antennae and four pairs of legs (as adults).
The mouthparts, called chelicerae, are adapted for piercing, sucking & lacerating.
Respiration is taken care by trachea but in absence of tracheal respiration, cutaneous
respiration plays role.
The mite life cycle generally consists of an egg stage, a larval stage, one or more nymphal
stages, and an adult stage.
The entire life cycle requires 1-6 weeks for completion.
Important species of mites:-
Common name Scientific name
Grain Mite Acarus siro
Mold Mite Tyrophagus putrescentiae
Cheese mite Tyrolichus casei
House dust mite Dermatophagoides sp.
Chicken Mite Dermanyssus gallinae
Two spotted spider mite Tetranychus urticae
Honey bee Mite Varroa sp.
Honey bee tracheal mite Acarapis woodi
Yellow mite Polyphagotarsonemus latus
Predatory mite Phytoseiulus persimilis
Cucurbitaceous mite Tetranychus cucurbitae
Mango mite Aceria mangiferae
Sorghum mite Oligonychus indicus
Cotton mite Tetranychus macfarlanei
Paddy mite Oligonychus oryzae
Citrus leaf mite Eutetranychus banksi
Sugarcane mite Schizotetranychus andropogoni
Cocunut mite Eriophyes guerreonis
Jasmine eriophyid mite Aceria jasmini

2. INTRODUCTION:-
Mites are pests of both animals & plants. Plant pests belong to the order Tetranychidae(spider
mite, so called because some of them weave webs on plants),Tenuipalpidae(false spider
mites),Tarsonemeidae(tarsonemids),Eriophyidae(blister or gall mites),& Eupodidae(eupodids).Of
these, the spider mites are the most important & prevalent.
BIOLOGICAL CONTROLOFPHYTOPHAGOUS MITE
Some of the predatory mites provide an effective control over the phytophagous mites by
voraciously feeding on them.
The use of predatory mites is an economical biological control for two-spotted spider
mites, a complex of harmful spider mite species, which feed on the undersides of plant
leaves.
Predatory mites are more effective than chemical control because the pest mites do not
build up resistance to predatory mites and growers can reduce or eliminate the use of
chemical pesticides. Spider mites are often a ‘secondary’ pest outbreak after spraying –

3. break the cycle by using predatory mites! Crop yield and quality also improves when
growers stop using broad spectrum chemical sprays.
Predatory mites do not bother plants, people or animals.
Because predatory mites do not give immediate control, they need to be released at the
first signs of a pest mite problem. If there are no pest mites for food, predatory mites will
not survive and reproduce. Some species (N. californicus and A. fallacis) persist at low pest
densities.
In these conditions, it is advantageous to use the ‘bean leaf’ product that carries a food
source for the mites while they establish in the crop.
A ratio of 1 predator per 10 prey mites is often adequate to suppress a pest population.
It helps to tolerate a small population of two-spotted spider mites in hot spots to
maintain the predators as long as possible during the season and be ready to recolonize
each year.
High density hot spots can be knocked down with “selective” miticides before and after
the release of predators.
Other insects are also important predators, including six-spotted thrips, Stethorus
punctillum, the cecidomyid Feltiella acarisuga, and general predators, such as minute
pirate bugs, big-eyed bugs and lacewings.
PREDATORYMITES DESCRIPTION:-
Typhlodromus pyri (Scheuten), Amblyseius fallacis (German), Typhlodromus
occidentalis (Nesbitt) (Acari: Phytoseiidae), and Zetzellia mall (Ewing) (Acari:Stigmaeidae)
Predatory mites can provide consistent biological control of pest mites such as the European
red mite (Panonychus ulmi), (ERM), and two-spotted spider mite(Tetranychus
urticae), (TSSM).
Pure or mixed populations of several predatory mites occur in New York tree and small fruit
plantings.
The most important of these predators are the phytoseiids, Typhlodromus
pyri and Amblyseius fallacis ,Metaseiulus occidentalis, another phytoseiid, is capable of
controlling pest mites, but it occurs only sporadically in New York orchards. Its behavior as a
predator is similar to A fallacis. Zetzellia mali, a Stigmaeid or yellow mite, can be found in
almost any orchard in the state, but provides biological control by itself only when ERM
numbers are relatively low.
Description andBiology:-
The predaceous mites discussed here pass through five stages: egg, larva, protonymph,
deutonymph, and adult. Larvae are six legged; nymphal stages and adults are eight-legged . When
on leaves, these mites are typically found on the underside near the midrib. Eggs are usually laid
along or under the midrib or other large veins, and quiescent forms are most often found there.
Typhlodromus pyri (TP) is common in commercial apple orchards in New York.
Amblyseius fallacis (AF) is virtually identical to TP, so a compound microscope is needed to
distinguish between them. AF overwinters in trees if preys are available in the fall. It can be found

4. in trees as early as bloom, but numbers are often very low until July or August because of high
winter mortality (greater than TP).
Voracity and feeding preferences of adult and larvae Stethorus gilvifrons were evaluated
in the laboratory on the Date Palm spider mite, Oligonychus afrasiaticus Larvae and adult
life stages a prey previously recorded for this predator. Adult of S. gilvifrons consumed
significantly more mites than Larvae.
The predator adults consumed 33.67 and 21.33, whereas predator larvae consumed 32.33
and 19.67 adults and larvae of 40 spider mites respectively in 24 h. The two life stages of
predator coccinellid showed a significant preference for adult’s O. afrasiaticus in the
presence of its larvae. This preference was more pronounced for adults of S. gilvifrons.
The total number of prey consumed decreased significantly for predator adult and Larvae
as the number of larvae mites increased in the prey ratio. Our results suggest that O.
afrasiaticus larvae is an alternative prey for predator, and that adults of S. gilvifrons
should be more efficient than its larvae in a prey assemblage with Larvae and adult of
mite.
In Brazil, for example, a program was successfully implemented in apple orchards to
control phytophagous mites using the phytoseiid Neoseiulus californicus.
Neoseiulus idaeus belongs to a group of selective predators of tetranychid mites, but its
prey range is relatively broad within these web-producers.
Stethorus gilvifrons is a biological agent of the date palm spider mite Oligonychus
afrasiaticus which is a serious pest of date palm in the southwestern of Iran. Adult and
larval stages of S. gilvifrons feed voraciously on different growth stages of O. afrasiaticus.
Predatory mites:-
Family: - Phytoseiidae
Description and life history:- There are several families of predatory are most important for
agriculture and horticulture because they are voracious predators of spider mites many of these
predatory mites are commercially available. Phytoseiid mites are 0.5-0.8 mm long and live in the
soil or leaf litter. They feed with a pair of needle like chelicerae which, when inserted into a plant or
herbivorous mite, allow the mite to suck out juices.
PREY SPECIES:- Although these mites almost always prey on other mites and small insect, many can
also feed on honey dew pollen during times of prey scarcity. Many Phytoseiid are generalized, but a
few have specific prey requirement. Phytoseiids are effective control agent due to their short
generation (1week), high fecundity (40-60 offspring per female), and hearty appetites (20 spider
mites/day, while developing and 10/day for 2-3 weeks as an adult.) Phytoseiulus persimiis is a
specialist mite that control webspinnig mites such as the two spotted spider mite.

5. Biological control of twospottedMite:-
Two spotted Mite control by Phtyoseiuluspersimilis
Persimilis is a voracious feeder on all stages of two spotted mite, a major pest of many
crops. It is one of the world's most commonly reared natural enemies and has been produced
commercially in Australia for over 25 years. This beneficial mite has been used successfully in

6. many situations including strawberries, greenhouse crops and deciduous fruits. The adult
predatory mite is orange, while the younger stages are clear. Both forms are pear-shaped and
fast-moving. Persimilis eggs are oval, tinged with orange and twice the size of spider mite eggs.
Adult persimilis feed on two spotted mite eggs, young and adults. Even though persimilis are only
slightly larger than the mites on which they feed, an adult can destroy twenty young or seven
adult two spotted mites per day. Juvenile stages of persimilis feed on eggs and larvae of spider
mites. At a temperature of 25°C, the predatory mites multiply twice as fast as their prey.
Targetpests:-
Twospotted mite Tetranychus urticae
Bean spider mite Tetranychus ludeni
Pests controlled by persimilis include two spotted mite, the major target pest, and the less
important bean red spider mite. Both belong to a group of eight-legged, plant- feeding mites
called spider mites. Two spotted mite is a major pest of many crops in a range of climates.
Beforerelease
Chemical residues toxic to predatory mites must have time to degrade before persimilis
are released. Synthetic pyrethroids and some organophosphates may need up to eight
weeks to break down.
There is a range of less hazardous chemicals which are preferred if spraying is necessary.
Inspect crops regularly for the presence of mites, especially on the windward side, in dry
spots and at edges. Introduce predators while infestation of two spotted mite is still in its
early stages. For instance, in strawberries, predators should be introduced when four out
of thirty full leaves have mites present.
Check the surrounding vegetation for sources of spider mite and treat these areas as well.
If a hot spot is detected early and treated quickly, the predators will move from that spot
and follow the mites as they spread. Details of the best timing and method of release for
various crops are available from suppliers.
If overhead irrigation is required it should be applied before introducing predators rather
than shortly after. Likewise, if it is raining or rain seems imminent, delay releases until the
plants are dry. Predators can be stored at 7 - 10°C for up to seven days.
At release
Persimilis are dispatched on bean leaves in packs of 10 000. These include persimilis
adults, nymphs and eggs, plus small numbers of two spotted mites as food for the
persimilis. Each pack contains over 300 individual leaves. Place these leaves into the
foliage of the infested plants.

7. Recommendedreleaserates
Field crops:- Minimum one pack of 10 000 mites per 1 000 - 2 000 m2.
Strawberries:- Minimum one pack of 10 000 mites per 3 000 - 5 000 plants.
Ornamentals and cut flowers:- Minimum one pack of 10 000 mites per 200 - 500 m2.
Other natural enemies of twospottedmite
 Black ladybird- Stethorus fenestralis
 Native predatory mites- Amblyseius spp
 Predatory mite -Typhlodromus occidentalis
 Predatory thrips -Scolothrips sexmaculatus
 Ladybird beetles -Coccinella repanda and Harmonia conformis
 Hoverfly larvae -Syrphus spp
METHODSOFAPPLICATION:-
Predatory mites will have the best chance of success if not more than 10 percent of
leaves have pest mites on them.
If there is more than an average of one pest mite per leaf, it is best to reduce the
population with an insecticide soap or selective miticide.
Broad-spectrum pesticides must be avoided for two to three weeks before the
introduction.
Distribute predatory mites when cool and avoid irrigation or hosing down foliage
immediately afterward if the mites are in a natural medium.
Water or sugar water sources and higher humidity improve their performance. Under
good conditions pest mite control is possible in four to six weeks.
Recommended quantities depend on many factors, including level of infestation
carried over form the previous season, ant control and whether selective miticides will
be used to treat hot spots.
When leafhoppers are also a problem, a combined program with green lacewings will
aid mite control.