cm at planting do not require shading. During warm summer temperatures (>35°C), the tubes should be removed from the trees, otherwise foliage within tubes can became heat-stressed and desiccated.
Use of tree shelters with pawpaw trees.
WEED CONTROL. Weeds and grasses can easily out-compete pawpaw trees for resources. Weed control is especially important during the first years of tree establishment and continues to be important after this period; this will optimize fruit production from mature trees. There are a number of organic weed control approaches within rows around trees that are options for a pawpaw planting. In organic farming, it is important to try to take a holistic cultural approach. The goal is not just control weeds, but to improve the soil organic content. Cultivation around trees from the drip line to the trunk can be used to control weeds; however, cultivation must be shallow (< 4 inches) to avoid damaging roots. The Weed Badger is an excellent tractor attachment for weed control (www.weedbadger.com). Wood chip mulch, straw, and hay (6-8 inch depth) can be used to mulch around trees for weed control and are usually effective method one to two years. Make sure that the straw or hay does not contain large quantities of weed seeds. For larger plantings, unroll round bales of hay in rows and use for mulching (6-8 inch depth). This method has been very effective in weed control and the hay degrades to add organic matter to the soil. Vole damage can be a problem with other fruit trees when using straw/hay mulch around the trunk; however, voles do not damage pawpaw trunks. This is likely due to the presence of acetogenin compounds in the bark. Flame cultivation can be used for weed control with pawpaw; especially around large trees. Flame cultivators, such as the Red Dragon Home & Garden Flamer, are commercially available; usually they consist of a torch like attachment connected to a LP gas tank. With flame cultivation, the flame is passed
in weed control and the hay degrades to add organic matter to the soil. Vole damage can be a problem with other fruit trees when using straw/hay mulch around the trunk; however, voles do not damage pawpaw trunks. This is likely due to the presence of acetogenin compounds in the bark. Flame cultivation can be used for weed control with pawpaw; especially around large trees. Flame cultivators, such as the Red Dragon Home & Garden Flamer, are commercially available; usually they consist of a torch like attachment connected to a LP gas tank. With flame cultivation, the flame is passed
Weed control using weed badger around trees in the University of Kentucky pawpaw planting.
Flame cultivation for weed control around pawpaw trees.
over the weeds just long enough to rupture the cells of the plant and kill the weeds. Be careful not to linger too long over weeds with the flame and start the weeds on fire! Additionally, do not direct the flame at the foliage or the tree trunk; the bark can be damaged and foliaged killed. Flame cultivation is not a good method with straw or hay mulch or during periods of low rainfall because of increased fire danger.
CROP ROTATION. NOP standards require that a grower implement a crop rotation in the orchard including but not limited to sod, cover crops, green manure crops, and catch crops that provide the following functions that are applicable to the operation: maintain or improve soil organic matter content; provide for pest management in annual and perennial crops; manage deficient or excess plant nutrients; and provide erosion control. With fruit trees, rotation of alley cropping, intercropping, and hedgerows are used to introduce biological diversity in lieu of crop rotation. Often permanent sod is used in the alleyways for the life of the tree and areas surrounding the orchard are rotated in a manner that increases biological diversity in the orchard. Crop rotation can be utilized in the alleyways with legume cover crops to increase the nitrogen available to trees. Unfortunately, there is not any scientifically derived information concerning the best cover crops (e.g. vetch, fava beans or lupins, etc.) to grow with pawpaw and not over compete with the trees. Cover crop recommendations may also vary by location in the U.S. There is additional information available at http://www.sarep.ucdavis.edu/ccrop/CCPubs/SelectingCoverCrop.html that may help guide growers in cover crops to try with pawpaw.
Round hay bale mulch pawpaw trees.
the NOP standards). Use of legume cover crops in alleyways can help provide additional nitrogen to trees. Growers should conduct a foliar analysis in July to monitor your fertilization program. Irrigation during establishment improves tree survival rates and in mature trees it will improve fruit size. Irrigation requirements will vary by soil type and soil depth. A soil depth of at least 3 feet will help provide a water reservoir for the tree.
NUTRIENT MANAGEMENT AND IRRIGATION. In organic production of pawpaw, nitrogen must be applied to trees for excellent growth (16 to 24 inches of shoot extension per year in establishing trees and about 6 inches in mature trees) and optimal fruit production. Organic feather, meat, bone and blood meal (such as 10-2-8 from NatureSafe\circledR) fertilizer can be broadcast under pawpaw trees before budbreak in early spring at 1 oz. N/tree the first year after planting, 3-4 oz. N/tree (about 50 lbs/A at 295 trees per acre) in years 2-5, and 5-6 oz. N/tree in year 6 and beyond. Compost is difficult to incorporate if woodchip or straw mulch is used around trees for weed control. Compost containing animal manure must meet specific temperature standards during production (see PEST AND DISEASE CONTROL. Pawpaw pest problems are limited and usually do not require control measures. Pawpaw leaves can exhibit leaf spot, principally a complex of Mycocentrospora asiminae, Rhopaloconidium asiminae, and Phyllosticta asiminae. Especially during wet years, fungal spot (Phyllosticta species) on leaves and the surface of fruit can lead to problems; infested fruit can to split during development. The pawpaw peduncle borer (Talponia plummeriana Busck) is a small moth larva, about 5 mm long, that burrows into the fleshy tissues of the flower causing the flower to wither and drop. Usually, the great abundance of unaffected flowers on trees does not require control of this insect. The zebra swallow-tail butterfly (Eurytides marcellus), whose larvae feed