Alliums: Garlic Harvest and Post-Harvest Considerations – Crystal Stewart-Courtens, ENYCHP
Setting up for success at harvest: As we move towards garlic harvest, there are a few things that growers can do to set themselves up for success. Careful water management, removing any diseased garlic from the field prior to harvest, and careful timing of the harvest all contribute to maximize the size and quality of the crop.
Cull diseased garlic now: Removing any garlic that is prematurely wilting/yellowing between scaping and harvest will help to ensure that you don’t bring diseased garlic into storage, where it could spread disease throughout the crop. If you don’t recognize a problem that you are seeing, seek help from your local CCE educators to get the issue properly identified, especially if it’s spreading.
Provide one inch of water per week to the crop: Alliums are essentially delicious water balloons and need adequate moisture to reach full size. If on plasticulture, plan to irrigate to deliver this amount of water weekly. If on bare or mulched ground, plan to supplement with irrigation if rainfall isn’t adequate. Stop watering at least one week before harvest to facilitate digging.
Harvest at peak maturity: Allowing garlic to reach peak size creates a better seal between the clove wrappers and the clove and between the outer wrapper leaves and the bulb. That seal is part of what decides a bulb’s longevity. Signals that the garlic has reached peak size include: waiting until the tips of the cloves start to pull away from the scape (hardneck), the cloves are bumpy rather than forming a smooth circle on the bulb, and a small gap forms between the cloves and the scape on the interior of the head.
Post-Harvest Handling Best Practices: There are several steps growers can take to help garlic dry quickly, which is the best way to reduce post-harvest disease issues. Topping the garlic, curing it in a warm, dry environment with good air flow, and then moving it to a cooler but also dry environment will help avoid issues ranging from black mold to eriophyid mites.
Topping garlic: We have conducted numerous studies on topping garlic prior to harvest and consistently find that it speeds drying and may also decrease the total mass loss over time. The height of the initial cut may range depending on your cutting tool, with anything longer than 1.5 inches working well.
Cure warm and dry: Similarly, curing at between 85 and 110 degrees with low relative humidity consistently yields garlic with reduced disease issues. Curing at the high end of this range at the end of the process may also help to kill eriophyid mites which are in the garlic bulb. Growers achieve these temperatures passively in high tunnels with shade cloth and fans running directed at the garlic.
Store cool and dry: When the garlic is dry, all wrapper leaves to the scape will feel dry to the touch. At this point you should move the crop out of the warm curing environment and into a cooler space. Any temperature below 75 degrees and 75% RH will avoid most surface molds, though temperatures much cooler, down to 40, will also slow eriophyid mite development if that is a concern.
Beans: Now that first cutting and small grains have been cut or are reaching maturity, keep an eye on your beans for leafhoppers as they will be moving out of those field crops and into beans and potatoes. They can also infest eggplant, causing a necrosis along the leave edges. Beans, especially young plants, are very susceptible to hopper burn which can lead to a reduction in yield and pod quality. Pyrethroids such as Warrior II, Mustang can be used, but multiple applications will probably be required. Another labeled material such as Assail (acetamiprid) will give you a week or more of protection and might be a good choice for younger plantings.
Brassicas: Flea beetles are still raging in most brassica crops, along with the usual worm pests including Imported Cabbage Worm and Diamondback Moth. Labeled conventional products for worm control include spinosyns (e.g. Radiant), pyrethroids (e.g. Warrior, Mustang, many others), diamides (e.g. Exirel and Coragen, Proclaim and Avaunt. Bt products are effective and selective for caterpillars—e.g. Dipel (OMRI-listed), Xentari, Biobit HP etc. The pyrethroids will also help control flea beetles but will require repeated applications. We are also seeing the impact from Cabbage Maggot feeding with plant wilting and death, especially now that plants are getting bigger. Not much you can do now as the damage is done. Late summer generations can impact late season plantings of brassicas and radishes. Take notes in which fields have had damage as the larvae will overwinter in the soil in these fields and try not to plant brassicas back in them next year.
Cucurbits: Striped Cucumber Beetles are out and in full force in many vine crop plantings so make sure you are scouting on a regular basis. If you planted transplants in which seed was treated with FarMore, don’t rely on it being there for control. Usually you can figure about 10 days to maybe 2 weeks of control, but those transplants are probably already 3-4 weeks old so they may need to be treated with a foliar insecticide. However, be mindful of applying insecticide applications where plants are in flower to protect our bee populations. Apply in the late evenings when bees are not as present in fields.
Every year the first disease that we see in cucurbits Angular Leaf Spot (ALS), a bacterial disease caused by Pseudomonas syringae. Initially leaf symptoms appear as small, irregularly shaped, water-soaked lesions. The spots expand until they are limited by larger veins, giving them the angular appearance which the disease is named for. As the spots dry, they shrink and tear away from the healthy tissue leaving large, irregular holes and giving the leaf a ragged appearance. Squash and watermelon leaf lesions are more variable in size than cucumber lesions which are usually smaller. The squash and melon lesions can be surrounded by a yellow halo. Lesions can appear on the fruit as well but will be more circular and are smaller than on the leaf. If left untreated, the ALS lesions will crack open, allowing secondary fungi and bacteria to invade possibly resulting in a slimy, foul-smelling fruit rot. Apply OMRI approved copper alone in organic production. Conventional growers can apply copper along with a fungicide like mancozeb (make sure you follow the PHI for mancozeb if harvesting green and yellow squash now) that can protect from secondary infection. Copper will help slow disease spread during particularly wet periods but can be dropped if dry weather continues for 2 weeks. For more information on management and pictures of ALS, click here.
Nightshades: Tomatoes are looking excellent in most places with staking and tying happening. Remember, do not work those plants when there is a heavy dew or after a rain when plants are wet. This is prime time for the bacterial pathogens, primarily Bacterial Canker, Speck and Spot to spread and also infect wounds created by pruning or rubbing the plant and creating just enough of a wound for bacteria to invade. I know I’ve also talked about this before – pruning is an important step in the staking and tying of tomatoes. However, pruning large suckers off can cause the plant to be set back. What’s a large sucker? Anything thicker then the diameter of a pencil probably shouldn’t be pruned off. First, it leaves a gaping wound and second, it’s a shock to the plant inevitably leads the plant to slowdown a bit. With that said, it’s a double edge sword – don’t prune and the plants get bushy and heavy and more likely to topple in a windstorm, in addition there is less air movement through the crop which can encourage disease. It takes longer to harvest because you can’t find the fruit and fungicide coverage becomes more difficult because you have more to cover. Not to mention fruit size is reduced when we don’t prune. Bottom line – get out there and prune early and often to help keep the suckers from getting too big! There was a report of Late Blight in Onondaga County back in mid-April in a high tunnel but, the grower quickly took care of it, and we haven’t heard of any new reports.
Potatoes are also looking fine except for Colorado Potato Beetles hatching in plantings. The best advice is to flag a couple of egg masses (little orange torpedo looking things laid in clusters on the undersides of the leaves) and monitor them daily. Once you have egg hatch, you can time your insecticide sprays to go after the smaller larvae, which is key with many of the insecticides we have labeled. Be sure to also keep an eye on eggplant which is a favorite source of food for CPB as well. Rimon, Radiant (Entrust for organic producers) and the chlorantraniliprole containing products (Coragen, Minecto Pro etc.) are still our best choices. From Sandy Menasha, Long Island Fruit and Vegetable Update: For growers using Rimon, it is so important to target small larvae to obtain the desired level of control. Rimon should be applied 2 times, 7-days apart, at a rate of 12 oz/A at each application, starting at 50% egg hatch or when small larvae are first observed. Max application rate per season is 24 oz/A. Other options include Radiant/Blackhawk applied at the highest labeled rate or Prokil Cryolite if weather conditions allow (3-4 rain free, sunny days in a row after application). Organic growers should be using Entrust or azadirachtin prodcuts (Azatin, AzaGuard, Azera, Molt-X, Aza-Direct, Ecozin Plus, Neemix). Apply these 2 times, 7-days apart, and apply at the highest labeled rate starting when small larvae are first observed.
Corn: After a dry start, sweet corn has really jumped the since the rain last week and will progress even quicker with the 90O days forecasted for early next week. There are some weedy fields out there, probably because herbicides didn’t get enough rain to activate them. The post-emergent materials to choose from can be found by clicking this link: Post Emergent Sweet Corn Herbicides. Impact or Armezon remains a very good choice for crop safety and weed control. Permit, Stinger and Accent Q are also labeled. Remember this: you need to know what weeds you are going after. Some materials are very specific and only control a narrow spectrum or even a couple of species, so you need to know which weeds you have in your field. Second, you will need to know the stage of your sweet corn in order to know if you can broadcast the materials or use drop tubes to keep the herbicides out of the whorl in order to reduce the chance of injury to the crop. As always, you need to really pay attention to the labels of these materials. You also need to add the correct surfactants and nitrogen to these materials to be the most effective – if you aren’t going to use them, the control will not be satisfactory.
