dubiousness : I ca n’t determine what is happening to my Pastinaca sativa . Could it be aphids ? What is wrong with my parsnip ? -Tim J.
response : Not much is potential to go wrong with your parsnip harvest if it is well - grown as part of a crop gyration . Several disease , such as downy mildew and foliage spot may be unsightly but they do not seriously affect the payoff of an otherwise salubrious crop . Canker is the bad problem and good finish is the good defensive measure against this .
Wireworm : gardens recently find from grassland or badly - tended garden meet most from this troublesome pest . The shiny sensationalistic larvae , which are about 2.5 cm ( l ” ) long , bore little regular hollow in most root crop , let in parsnips . Small roots may be almost entirely eaten up .
Keep wireworm down by careful weeding and polish . Treat very seriously infected state with diazinon or bromophos , and do not plant Pastinaca sativa or other susceptible crop for four or five days .
Celery fly : although this pest is not as serious on parsnips as it is on celery , it can still do sufficient price to reduce growth appreciably , because its attacks interpose with the chlorophyll - making mechanism of the leaf . The tiny 0.5 cm ( 1/2 ” ) grownup fly lay eggs on the foliage and the small maggot which emerge tunnel into and through the leave , producing livid or brownish blisters as they go . unremarkably , unspoilt cultivation will start the plant to uprise back after attack , but in the worst casing the most badly affected farewell should be take away and the balance spray with malathion . Alternatively , you’re able to belt down the maggots by twitch them , still in the leaf , between your finger and quarter round . If you are particularly troubled by this pest , paraffin series - soaked tag cling near the parsnips helps discourage the fly ball from lay eggs .
Carrot fly ball : the green - calamitous carrot fly lays its ball in the soil near carrots , parsnips or celery to which it is pull in by the smell of the leafage . The eggs hatch to produce small , pale yellow maggots which invade the root . These pests are also a problem because the wound they cause provide a starting point for canker sore .
Carrot fly is most likely just after thinning because the smell of the damaged foliage of the thinned plants attract them . Thin in the evening when the flies are less potential to be participating , and burn all the thin plants . Firm the soil around the works after thinning as this fills in the fissure in the soil and dissuade the flies from lay egg . As with cultivated celery fly sheet , paraffin - dowse tag avail to deter them . If the problem persists , dust with bromophos according to the manufacturer ’s program line .
Aphids : in a wry summer , greenfly can infest the leaf in large numbers racket , so that the leaf curl , become yellowish and even end to grow . This is more potential to take place in teetotal weather if the plant have not been water on a regular basis . Pick off the worst affected leaves and spray the remainder with derris or bioresmethrin .
Canker : this is the most serious job with parsnip . It appear as firm brown or fatal piece on the shoulder joint of the root which then becomes soft and rotten . The secondary putrefaction which follows the initial discoloration is due to fungus or bacterium , but the ground for the original discolouration is not known . It is most probable , however , that infected roots have been damage in some path , perhaps by Daucus carota sativa fly , by crack make by heavy rainwater after drouth , or by regardless hoeing . Because Pastinaca sativa are not self - healing ( as potatoes are , for example ) , filth - borne kingdom Fungi and bacteria can enter and molder the root .
The only remediation is well cultivation . acidulous stain and over - manuring with unrotted manure are say to encourage canker sore and these should be avoid . Try , also , later - sow crop , as these are more resistant .
Virus : mottled icteric leaves and scrawny plant are signs of parsnip virus . As with all virus there is no therapeutic . take out up the moved plants and burn them . Powdery mildew : parsnip leaves are occasionally attacked by this fungus which appears as a okay blanched powder on the surface of the leaf . It is most widespread in moist geezerhood but even then it does not seriously touch on the ontogenesis of the plants , and can be brush aside .
puberulent mold : downy mildewappears as moist , dark chocolate-brown or fateful spots on the leaves but , again , it is not serious .
leafage spot : a third disease which attack Pastinaca sativa leaves is leaf touch which produces pocket-size browned speckle on the leaves . Again , do not worry . The disease does not do enough hurt to virtue controller standard .
Sclerotina rot : this disease only attack ascendant in store , the roots becoming covered with a fluffy , white mold . To prevent bunk , only store in a teetotal , airy place and do not store damaged stem .
