Phoretic relationship between the myceliophagous mite Microdispus lambi (Acari: Microdispidae) and mushroom flies in Spanish crops

Abstract

We studied the role played by the phorid Megaselia halterata (Wood) and the sciarid Lycoriella auripila (Winnertz) in the phoretic dispersion of the myceliophagous mite Microdispus lambi (Acari: Pygmephoridae). Twenty-four crops were monitored during 18 months in commercial mushroom farms in Castilla-La Mancha (Spain). Adults of both species were collected weekly and the mites they carried were counted and identified. Both phorids (19.6%) and sciarids (4.4%) carried the mite M. lambi. The calculated load of each was 3.4 M. lambi mites per phorid and 1.9 per sciarid. The same percentage of male and female phorid was used as vector, but the load was slightly higher for females (1.86 mites per female compared with1.48 mites per male).A mean of 7.2% of the phorids examined in winter were vectors of M. lambi, while in spring and autumn of the first year the average was more than 22%. The mean load did not vary significantly between seasons. Inside the mushroom farms, less than 10% of a small initial population of phorids carried mites (less than two mites per phorid). As the cycle progressed, more than 35% of a larger population of emerging flies did so (average 3.5 mites per phorid vector). At the end of the growth cycle, the flies may fly off to colonise nearby farms, favouring the propagation of M. lambi from infested to uninfested crops. Megaselia halterata is the principal vector of M. lambi in the mushroom farms of Castilla-La Mancha due to their high numbers, the high percentage carrying mites and the number of M. lambi they carry.

Cultivation of Agaricus bitorquis mushroom as an strategy for the Integrated Pest Management of the myceliophagous mite Microdispus lambi

“…It is possible that the absence of mites in A. bitorquis crops could be due to the low presence, in these farms, of the phorid flies, that are the main phoretic vectors for mites in A. bisporus farms. 24 The results of the present paper point to an important presence of phorid flies on A. bitorquis farms, normally higher than on A. bisporus crops (Fig. 1(b)).…”

“…This is because of the high number of phorid flies, which are more abundant than sciarid flies (Lycoriella auripila Winnertz (Dipera: Sciaridae)) in Spanish farms, 22,23 and due to the high percentage of phorids that carry mites and the number of M. lambi that each phorid fly can carry. 24 Megaselia halterata is one of the most serious arthropod pest problems affecting the cultivation of mushroom throughout the world. [25][26][27][28][29] The preference of phorids for different cultivation materials, 26,27 different species of mushrooms 30 or, even, different isolates of one particular mushroom species 31 has been studied, and it has been found that they probably support the development of M. halterata in different ways.…”

Mushroom Phorid Flies—A Review

“…The insecticides aldicarb and chlorpyrifos-ethyl, incorporated in compost, were also proved to be effective to preclude adult emergence and reduce the incidence of sporophore damage by the larvae of M. halterata, although a decreasing yield associated with the chemical treatment was also noted [80]. As recently reported, flies preferably enter into the crops after the application of the casing layer on top of the colonized compost [18]. Accordingly, it would be more advisable to apply the pesticide on the casing layer instead of in the compost; regarding time, this would occur approximately 14 days after spawning or 20 days before the harvesting period begins, thus ensuring the safety of the product.…”

“…Likewise, early interruption of the crop cycle after harvesting the third flush would prevent the spread of the pest. Such a maneuver not only minimizes the risk of insect entrance from outside to the farm but also reduces the chances of pests spreading on the farm from affected to nearby uninfected crops [18,20], while also contributing to minimize the dispersal of harmful fungal diseases such as the dry bubble (Figure 1).…”

“…Reported evidence points to the transport of spores of different species of pathogenic fungi by mushroom flies [8][9][10][11][12][13][14]. Similarly, phorids as well as sciarids were described as vectors of pathogenic mites [15][16][17][18].…”