There’s nothing extra refreshing than a slice of homegrown watermelon on a heat summer season’s day. Rising watermelon is a enjoyable and rewarding expertise that’s not too completely different from rising cucumbers, pumpkins, or squash.
Sadly, there are a handful of ailments that it’s good to be careful for when cultivating watermelon. These ailments are each fungal and bacterial in nature. Some are simple to deal with, however others have no remedy. For those who’ve invested rather a lot in watermelons this 12 months, it’s essential that you just arm your self with data.
Whether or not you believe you studied your watermelon vegetation might have a mysterious sickness and wish to deal with it, otherwise you simply wish to know find out how to stop frequent watermelon ailments, we’ve bought you lined.
Anthracnose
Anthracnose is a foliar illness attributable to the pathogen Colletotrichum obiculare. It impacts all above-ground parts of watermelon vegetation, together with the leaves, the stems, and even the fruit.
This illness is especially dangerous as a result of it may destroy complete vines and trigger fruit decay. Generally, the anthracnose spots on fruits are neglected once they’re small after which harvested fruit decays and leaks unexpectedly.
Signs of anthracnose embody:
- Small, brown spots that first seem on the foliage. These spots could also be round or considerably angular.
- Brown spots that develop bigger till they crack.
- Related spots and lesions on the petioles and the vines, additionally rising in measurement.
- As these spots proceed to look and develop, you might uncover that complete vines have died.
- Small spots on melons which are principally round.
- Rising spots on melons that crack, sink into the flesh, and trigger decay.
For those who uncover anthracnose in its early levels, you might be able to deal with it to some extent. Take away and destroy any visually affected parts of the plant. Apply fungicide each week in humid environments or each two weeks in additional arid environments. Fungicides with chlorothalonil could also be efficient.
There are a number of steps you’ll be able to take to forestall anthracnose:
- Begin your season with disease-resistant varieties, equivalent to ‘Crimson Candy’ and ‘Charleston Grey.’
- Rotate crops in order that melons and cucumbers are usually not planted in the identical spot inside a 3-year window.
- Apply a thick layer of mulch over the soil to forestall soil-borne pathogens from splashing onto melon vegetation when it rains.
- Present area between every melon plant, and prune often to forestall the unfold of anthracnose from leaf to leaf.
- For those who’ve had bother with anthracnose in years prior, think about making use of preventative fungicide as an alternative of ready to see if the illness returns.
Bacterial Fruit Blotch
Bacterial fruit blotch is a illness attributable to the micro organism Acidovorax citrulli. The illness first appeared in 1989 in Florida and has been decimating harvests ever since. Although the illness does little injury to foliage, it may trigger yield losses of fifty p.c.
The illness is most dangerous to melons however may injury cucumber, pumpkin, and zucchini. Giant, off-color “blotches” kind on fruit, offering a pathway for pathogens to enter. These secondary pathogens trigger fruit decay.
Signs of bacterial fruit blotch embody:
- Small blotches could also be seen on cotyledons shortly after germination, however they’re simple to overlook.
- These blotches turn out to be brown, small spots that don’t look significantly threatening and don’t broaden a lot.
- When fruits first emerge, they might have small blotches on their floor.
- As fruits mature, these blotches turn out to be bigger and will cowl half the fruits’ floor.
- Contaminated fruits will decay as pathogens enter via these massive blotches.
As soon as detected, bacterial fruit blotch could be very tough to deal with. Gardeners ought to depend on preventative measures to keep away from bacterial fruit blotch within the first place. Nonetheless, ought to the illness emerge, you could have some success making use of copper-based fungicide. Start weekly software earlier than the plant flowers and proceed till fruits are harvested.
These are a number of steps you’ll be able to take to forestall bacterial fruit blotch:
- Hunt down disease-resistant varieties.
- Buy symptom-free transplants from dependable growers.
- On the finish of every season, take away any watermelon particles out of your backyard.
- Take away any watermelon seedlings that emerge in the course of the rising season.
- Rotate melon crops, maintaining them as distant from the place they have been grown beforehand as attainable.
- Use drip-tape irrigation and keep away from overhead watering as a lot as attainable.
- Ideally, take away and destroy any affected crops as quickly as you believe you studied the illness.
Gummy Stem Blight
Gummy stem blight is a foliar illness attributable to Didymella bryoniae, a fungal pathogen that causes cucurbits to rot. This blight can have an effect on vegetation at any stage of their progress and might injury all elements of the plant, together with the fruit.
“Gummy stem” refers to when the illness assaults the stems of the plant, inciting a gummy ooze, although that is extra frequent with cantaloupe. Watermelon vegetation normally expertise gummy stem blight on their leaves.
Signs of gummy stem blight embody:
- Darkish leaf spots on the leaves that may be as much as an inch in measurement. These spots normally happen across the margins of leaves.
- Leaves with a number of spots will die off.
- Watery, oozing stems.
- You might even see small, black dots on the plant’s petioles. There are the fruiting our bodies of the fungus that causes gummy stem blight.
Remedy choices for gummy stem blight are restricted as soon as it takes maintain. You possibly can attempt treating it with fungicides. Merchandise with chlorothalonil and mancozeb could also be efficient. Honestly, it is best to take away any watermelon vegetation contaminated with gummy stem blight as a preventative step for subsequent 12 months.
There are a number of extra steps you’ll be able to take to forestall gummy stem blight:
- Observe crop rotation. Wait a minimum of two years earlier than planting watermelon or different cucurbits in the identical spot.
- Apply fungicide preventatively if you understand you’ve had points with gummy stem blight previously.
- Alternate fungicides from 12 months to 12 months, as gummy stem blight is proof against some fungicides.
- Use drip-irrigation and keep away from watering from overhead. Splashing can unfold the illness.
- Apply a thick layer of mulch on high of soil in an try to forestall leaves from making contact with pathogens residing within the soil.
Downy Mildew
Downy mildew is a illness unfold by Pseudoperonospora cubensis, a kind of water mildew. The illness may cause foliar loss to such a level that watermelon yields are decreased. Lack of leaves may go away fruits uncovered to an excessive amount of solar, resulting in sunscald.
Many decorative and edible vegetation are topic to downy mildew, one in all which is watermelon. To not be confused with powdery mildew, which seems to be like a grey powder, downy mildew first seems as yellow splotches that fade to brown.
Signs of downy mildew embody:
- Yellow or gentle inexperienced splotches on the oldest leaves of the plant.
- Splotches that get greater, flip brown, and slowly cowl newer leaves.
- Leaves that turn out to be consumed with downy mildew shrivel up and fall off their petioles.
- The petioles and stems will stay and seem wholesome, which helps differentiate downy mildew from anthracnose.
- Fungal progress on the undersides of leaves, comparable to splotches on the leaf floor.
For those who suspect downy mildew in your watermelon vegetation, take away the contaminated leaves instantly. If attainable, use shade material to guard newly uncovered fruits. It’s also possible to try and deal with downy mildew with fungicides, together with chlorothalonil, copper, and mancozeb.
There are a selection of steps you’ll be able to take to forestall downy mildew:
- Apply fungicides (equivalent to chlorothalonil and mancozeb) preventatively, earlier than downy mildew seems.
- Water by way of drip-irrigation to reduce leaf wetness as a lot as attainable.
- In periods of excessive humidity, examine watermelon leaves often for early indicators of downy mildew.
- Maintain your eye on on-line downy mildew forecasts, such because the Cucurbit Downy Mildew Forecast, which tracks the illness by way of airborne spores.
Notice: Downy mildew solely survives on residing vegetation. Because of this it doesn’t reside within the soil over winter, so crop rotation may have no impact.
Fusarium Wilt
Fusarium wilt is a soilborne watermelon illness that’s attributable to Fusarium oxysporum, a fungal pathogen. It’s a drawback for a lot of plant species, together with solanaceous crops and lots of ornamentals. It will possibly unfold via soil, seeds, and the air.
Gardeners must hold a severe eye out for Fusarium wilt, as a result of it may kill complete vegetation and does so earlier than any ripe melons are prepared to reap. Particular person vines endure first, however finally, the whole plant will die. This illness is especially insidious since it may destroy many plant species.
Signs of Fusarium wilt embody:
- Particular person vines might first seem uninteresting or start to wilt.
- Affected vines proceed to battle, turning brown earlier than dying off.
- You might even see massive brown splotches close to the crown of the plant, and when it rains, you might even see pink mildew on these splotches.
- Lifeless vines might have brick-red coloration once you minimize into them.
There may be no remedy or remedy for Fusarium wilt. Since this illness will kill watermelon vines earlier than they produce fruit, there is no such thing as a motive to try to salvage or deal with diseased vegetation. Take away them solely and destroy them. It’s tough to handle.
These are the steps it is best to take to forestall Fusarium wilt:
- Select watermelon varieties which are proof against Fusarium wilt, equivalent to ‘Crimson Candy’ and ‘Charleston Grey.’
- Observe aggressive crop rotation. Wait a minimum of 5 years earlier than planting once more in a website that had Fusarium wilt. Research have discovered that planting furry vetch as a canopy crop reduces Fusarium wilt within the meantime.
- Contemplate avoiding areas with a historical past of Fusarium wilt solely.
- All the time take away any vegetation you believe you studied of getting Fusarium wilt and sanitize your instruments afterwards.
Angular Leaf Spot
Angular leaf spot is a bacterial illness attributable to Pseudomonas syringae pv. lachrymans micro organism. It impacts many cucurbit species, together with watermelon. Angular leaf spot will not be as lethal to watermelons as a number of the different ailments on this listing, although it does trigger superficial lesions on fruit. Generally, these lesions grow to be rot.
Moreover, the micro organism that causes angular leaf spot cannot solely enter the fruit but in addition the seed and contaminated seeds can infect fields. This is the reason it is best to by no means accumulate seeds from watermelons or different related fruits that you just suspect might have had contact with angular leaf spot.
Signs of angular leaf spot embody:
- Small, angular brown spots on leaves have a yellow ring round them. These spots shall be positioned alongside the veins of the leaves.
- These spots will dry out, turn out to be brown, after which fall out of the foliage, leaving holes behind.
- Small, watery, brown marks on fruit that will rot.
- When contaminated leaves get moist, they might have a white liquid on their undersides. That is the micro organism spreading.
For those who suspect your watermelon vegetation have angular leaf spot, you’ll be able to attempt making use of a copper fungicide. This may increasingly gradual the unfold of illness in the event you begin early, defending wholesome plant tissue. As soon as it’s progressed considerably, there’s not a lot you are able to do.
Take these steps to forestall angular leaf spot:
- Hunt down disease-resistant varieties, and all the time purchase seeds from respected sellers.
- Observe crop rotation, ready a minimum of two years earlier than planting cucurbit crops in the identical spot.
- Use drip-irrigation to keep away from getting the leaves moist, and by no means deal with the leaves when moist.
- All the time observe wonderful sanitation together with your instruments and palms when coping with watermelon, so that you don’t unfold the micro organism.
Verticillium Wilt
Verticillium wilt is attributable to the fungus Verticillium dahliae. It will possibly infect a protracted listing of vegetation. The illness will kill complete watermelon vines earlier than killing the entire plant. Because the vines and leaves die off, remaining fruit might battle with sunscald.
Verticillium wilt has rather a lot in frequent with Fusarium wilt. Signs of verticillium wilt embody:
- Yellow chunks on leaves might seem shortly after the plant has first set fruit.
- Leaves will wilt and die alongside particular person vines.
- After particular person vines die, the whole plant might observe.
- Whereas the inside of useless vines has a reddish tint when vegetation have Fusarium wilt, they’ll have a lighter, brown tint with verticillium wilt.
There may be no remedy for verticillium wilt. As soon as contaminated, it’s solely a matter of time earlier than vegetation die. It is best to take away contaminated vegetation as an early type of prevention for subsequent 12 months’s crops, particularly since so many species are prone to verticillium wilt.
Make the most of these prevention strategies to keep away from issues with verticillium wilt:
- Observe excessive crop rotation and think about avoiding areas with a historical past of verticillium wilt altogether.
- Don’t plant watermelon proper after cotton, peanuts, or potatoes, which additionally battle with this illness.
- Think about using a plastic tarp as a mulch layer between the soil and your watermelon vegetation.
Key Takeaways
There are a handful of ailments that may critically hurt watermelon vegetation. As soon as you notice many of those signs, the perfect factor you are able to do is normally take away the vegetation solely. To forestall illness, observe crop rotation, hold your instruments clear, and develop resistant varieties at any time when attainable.