User:Morri362/asparagus miner

Overview
The asparagus miner (Ophiomyia simplex Loew; Diptera; Agromyzidae) is a specialist on asparagus (Asparagus officinalis L.) and is a problem for asparagus growers. It is shiny black and occurs in most major asparagus producing regions of the world.

Identification
The asparagus miner is a bivoltine stem-mining fly and a major pest of asparagus. It is small (~2-5 mm) with a shiny black body and black legs. Under a dissecting microscope or with a hand lens, one can confirm the identity of the fly by checking that the costa (the thicker marginal vein) ends at vein R4+5. In addition, the fly has five conspicuous orbital bristles emerging from the middle of its head. The maggots (immature stages) may be up to 5 mm long, and can be found feeding internally in asparagus stems. They are creamy white in appearance, with the anterior spiracles on short stalks. The pupae are darker brown or reddish, and can sometimes be seen as dried skin from the stem peels back around parts that have been mined.

Distribution & History
The asparagus miner occurs in most major asparagus producing regions of the world. The fly was first described by Loew from Pennsylvania, New Jersey and New York in the United States in 1869. However, because it is host-specific to asparagus, it was likely introduced to the United States from Europe when asparagus was brought over by settlers. It has been recorded from Germany, Great Britain , France , , Canada , other locales in the United States , , and many other countries. The species was originally described as Agromyza simplex, was moved to Melangromyza simplex and its current species name after revisions is Ophiomyia simplex.

Fungal Vector
The miner is a possible passive vector of pathogenic species of fungi that are responsible for the development of Fusarium crown and root rot and early decline of fields. Species in this fungal complex include Fusarium oxysporum and Fusarium proliferatum, among others, and these can shave 5-8 years off the economic life span of an asparagus field. The fly may passively vector the fungi from spores injected into the asparagus plant from the ovipositor or the sites of mining damage may create entrance points for the fungal spores from windblown sand.

Life Cycle
Adult asparagus miners emerge in mid-May in the northern United States, and seek out recently planted asparagus fields that have gone to fern , which may be especially vulnerable to infestation by the fly. First generation adults peak in abundance during mid-June. After mating, females lay eggs at the base of asparagus stems at the soil surface level or just below. Upon hatching, maggots undergo three larval instars or stages before pupating underneath the stem of the asparagus plant. As they develop, the asparagus miner feeds on cortical tissue. After pupation, the second generation of adult asparagus miners peaks around mid-July to mid-August in the United States. The end of adult flight happens in October and the asparagus miner overwinters as a pupa inside senesced asparagus stems.

Management
An integrated pest management program should be established in problem fields that combine 1) monitoring using yellow sticky traps or scouting, 2) use of degree-day model to guide decisions about spraying (Morrison, in press), and 3) enhancement of biological control from the natural enemies of the asparagus miner. The degree-day model can be accessed in the near future on Enviroweather’s website, a free service maintained by Michigan State University Extension and tied into a state-wide network of weather stations. Research is currently ongoing in the investigation of which flowering resources benefit the natural enemies of the asparagus the most  . Currently, growers apply broad spectrum pesticides, most commonly Sevin, to treat for adult asparagus miners in the field. Coupling this management action with the degree-day model may allow growers to save money on chemicals and spare unneeded environmental costs.