About Insect Pest of Mushroom

1. INSECT PESTS OF MUSHROOMS AND THEIR MANAGEMENT
Cultivated mushrooms are subject to attack by a variety of pests especially during warm
weather. Some of these may be brought through compost, while others feed normally upon
mushrooms and are attracted from outside. Injury by these pests frequently becomes serious.
Invertebrate pests of mushroom
A variety of small fly and midge species are pests of mushrooms. The larvae feed on the fungal
mycelium in the compost, but may also tunnel into the fruiting bodies. A range of mite species
may affect the mushroom crop. Some directly damage the fruiting bodies, some may attack the
mycelium and some mites are predatory on other mites, fly eggs, nematodes or bacteria. Mite
damage the fruiting bodies, often shows up as small cavities in the stem and cap similar in
appearance to bacterial pit disease. Mycelium-eating mites can cause high yield losses. Mites are
very small and easily transported on clothing and tools. Springtails are commonly associated
with compost and can damage to the crop if present in high enough numbers. Slaters and
millipedes may also cause damage to the fruiting bodies.
Table: Insects infesting cultivated mushroom
Insect Order : Family Habit of larva Damage
Lycoriella castanescens
(auripila) and L. ingenua
(mali), Bradysia. difformis
(paupera) and B. lutaria
Diptera : Sciaridae Compost
(sometimes larva
in the stalk)
Mycelial loss;
damage to the
fruiting bodies
Megaselia halterata Diptera : Phoridae Compost bags No visible damage
Heteropeza pygmaea and
Mycophila speyeri.
Diptera :
Ceccidomyidae
Compost bags No visible damage
Pullimosina heteroneura Diptera :
Sphaeroceridae
Compost Mycelial loss
Drosopila funabris Diptera :
Drosophilidae
Fruiting body Fruiting body
Mycodrosophila sp. Diptera :
Drosophilidae
Fruiting body Fruiting body
Gyrophaena spp. Coleoptera : Fruiting body No visible damage

2. Staphylinidae
Triplex spp. Coleoptera :
Erotylidae
Adults on the
fruiting body
(larvae not seen)
No visible damage
Spring tail Collembola :
Entomobrionidae
Compost Mycelial loss
Mushroom flies and their life cycles
The main fly pests occurring in mushroom crops are sciarids, phorids and cecids.
Sciarids
Sciarids are the most important pest of mushrooms. These are compost feeders and prefer
unspawned compost to that colonised by Agaricus mycelium. The adult flies are attracted by
volatiles given off by the compost so are a danger at any time after pasteurisation when the
compost is cool. The adults are usually 3-4 mm long and with the naked eye can be distinguished
from the other fly pests of mushrooms by their long antennae. The females deposit between 50 to
200 eggs in the compost and the developing larvae pass through four moults varying in size from
1 to 8 mm long before pupating. Larvae are white, less than 1 cm long with a distinct black head
capsule. These larvae feed on mycelium, "pinheads" and small mushrooms and also tunnel in the
stalks and caps of larger mushrooms. Such feeding can result in a yield loss of 40% but a more
usual figure is less than 10%. They are easily recognised by their black shiny heads. They feed
on rotting vegetation, so mushroom compost is an ideal substrate for them but the accumulation
of their waste renders it unsuitable for mushroom growth. Although, exudates produced by the
growing Agaricus mycelium inhibit the larvae, they have been observed browsing on the
growing tips and when there is a large infestation the larvae will burrow up into the mushroom
stipes. Their major significance is that adults are mainly responsible for disease spread. Sciarids
are predominantly casing inhabitants and the usual chemical control is by treatment of the casing
soil.
Phorids :

3. Phorid larvae are obligate mycelial feeders therefore the adult flies are not attracted to oviposit in
the crop until spawn run. Adults resemble diminutive houseflies, blackish in colour, shorter in
proportion to their width than sciarids and have inconspicuous antennae. Adults are very strongly
attracted to compost or casing in which spawn is running. The larvae are white, 1 to 6 mm. long,
are stubby at one end and have a pointed head at the other. They feed on the growing mushroom
mycelium but rarely feed on the fruiting body. They can be distinguished from sciarid larvae by
the absence of black head and they develop more rapidly into a pupa. The adult fly is 2 to 3 mm
long, has very short antennae and a characteristic hump-back. It can be distinguished from the
sciarid fly by the short antennae and by its rapid, jerky, running movement. Phorids are
essentially compost dwellers and chemical control involves the addition of an insecticide to the
compost.
Ceccids
The larvae of ceccids are obligate mycelial feeders as with the phorids, while the dults are small,
delicate, straw coloured flies. Ceccids can produce a new generation every 4 to 7 days and each
‘mother’ larva can produce up to 12 new larvae so numbers can increase exponentially. The
larvae suck the contents from mycelial hyphae, thus reducing yield. Due to their remarkable
facility for population increase huge numbers of larvae migrate from the compost and spoil the
crop by carrying bacteria that cause breakdown of the stem surface and gills. Larvae of the
commonest species are white but occasionally species with orange larvae occur. These are much
more noticeable as mushroom contaminants. When there is a bad infestation, the larvae clump
together and flow over the sides of the mushroom beds onto the floor where they can be
inadvertently transported to healthy crops on feet and equipment.
Tarsonemid Mites are minute white mites, invisible to the naked eye. These mites feed on
mycelium causing the infested mushroom to develop an ‘off white’ colour. Sometimes the base
of the stem can become reddish-brown, development of mushrooms is restricted and mushrooms
are poorly anchored in the casing. Usually, symptoms are not seen until near the end of the
cropping cycle. Their presence indicates poor hygiene. Adoption of good hygienic practices can
effectively serve as control.
Predatory mites

4. Parasitus fimetorum, Digamasellus fallax and Arctoseius cetratus are the predator mites which
are found in the growing rooms. These mites are bigger in size and faster in movement than other
mites. These predator mites feed on nematodes, smaller mites and the eggs and larvae of other
mushroom pests. Therefore, they can be considered as helpful insects on different stages of
mushroom cultivation. But on the other hand, the presence of predator mites indicates the
presence of their source of food, that is, the more mites, the more other pests there are. This in
turn means something went wrong during the compost preparation process and its pasteurization
and that there are some problems in the sanitary state of the farm. Despite the fact that predator
mites only benefit the mushrooms, they cause discomfort for the working personnel because they
easily stick to clothes and hands causing unpleasant sensations. When predator mites appear, it is
advised to test the whole batch of compost to detect their source of food and take measures
against the real mushroom pests.
Nematodes
Saprophytic nematodes are not considered to be mushroom pests. With their oral cavity that
looks like a tube, they suck in organic nutrients and microorganisms and especially bacteria that
exist in great amount in compost and in the casing layer. That is why poorly prepared and
pasteurized compost is not well suited for the development of mushroom mycelium, but is a
favourable environment for the nutrition and reproduction of nematodes that have survived
pasteurization. In non-selective substrates with overly humid areas, nematode population grows
incredibly fast. The toxins they release and the increasing number of putrefactive bacteria
weaken the mycelial growth. The compost becomes watery and darkens with the production of
objectionable odour in the room because of putrefactive bacteria. When the infection is severe,
the nematodes swarm in great amounts on the casing surface. They form columns that look like
erect waving sticks and thin threads that flicker in the light. In this condition, nematodes are able
to adhere to flies, mites and personnel that harvest mushrooms.
Management of insect pests of mushroom

5. Cultural Control
 Hygiene – Before cropping, cleaning and disinfection of growing tunnels, utensils and
containers is an important aspect of ceccid and tarsenemid mite control. In fact such
measures are the only steps one can take to avoid such pests.
 Exclusion of flying insects - This is a most important aspect of fly control in mushroom
houses. Air inlets should be fitted with a mesh with apertures not greater than 0.5-0.6
mm. Doors should be seated against an intact rubber seal like that of a commercial
refrigerator. It is important to keep doors closed in so far as possible, particularly during
spawn run.
 Quick transport of spawned compost to the house avoids exposing it to egg laying by
sciarids and phorids.
 Regulating house temperature to achieve a quick spawn provides competition for pests
for resources in their ecological niche.
 Reducing the production cycle to reduce the potential for pest build-up can be a very
useful pest suppression tool.
 Using traps to monitor fly numbers increases growers awareness of low fly populations.
Low fly populations especially during spawn run are of major importance as they give
rise to the initial infestation which culminates in the high populations that occur later in
the cropping cycle and result in economic injury. It is also important to continually
check crops for pests, determine the extent of the problem, treat as appropriate and
evaluate the effect of the treatment.
 If pesticides are to be used, use the most appropriate one, apply evenly, apply at the
correct dosage, the right time and under the right conditions.
Chemical control
Newly spawned substrates have to be protected from flies. In some cases, in order to
control flies, insecticides are added to the compost. When using insecticides in the compost, it is
very important to mix and distribute the compound evenly, because the effect of the insecticide
basically depends on the mixing thoroughness. It is important for the insecticide and the
mycelium to be as far from each other as possible during the spawning process, because at close
contact, the insecticide has an adverse effect on the subsequent mycelium growth and fruit body

6. formation. Therefore, mycelium and insecticide shouldn’t be applied to the compost at the same
time. Regardless of the compound’s formula, it should be applied to the compost before
spawning. That will help escape the covering of the mycelium with an insecticide. The treatment
of compost will provide protection only during spawn run. The absence of protection after the
application of casing layer can lead to the infestation of the casing soil with parasites and can
therefore cause damage the mycelium on the surface of compost and casing layer. The materials
used to prepare the casing soil and prepared casing soil should be stored in a clean room. If any
pests are present in the casing soil, it has to be treated with formalin or pasteurized with steam.
When the insecticide is applied during the casing soil preparation, it should be mixed uniformly
and the compound has to be spread throughout the whole mass of the casing layer.
The larvae of some flies are easily spread throughout the farm, therefore, it is necessary
to isolate the growing rooms using mats for footwear, that have been treated with a disinfectant.
Necessarily disinfect the working instruments and use different working clothes in each growing
room.
In the end of cultivation cycle, the spent batches and growing rooms must be disinfected. All
spent compost must be immediately removed from the farm. The empty growing rooms must be
thoroughly washed with a disinfectant.