14 articles tagged "Strawberry".

Figure 1. Strawberries are growing in a high tunnel.

Strawberries have a rich flavor; sugar, acid, phenolic content, and aroma all together make the wonderful fruit. Many factors are assumed to affect strawberry flavor. Some are supported by scientific evidence, some may be simply people’s impressions. In this article, we discuss some of the factors that are more likely to affect strawberry flavor. Locally grown strawberries often taste better than strawberries purchased from grocery stores. Part of the reason is that strawberries shipped long distances are harvested a few days before they are fully ripe. The fruit has longer shelf-life but the flavor is sacrificed. We are testing ten strawberry varieties in a high tunnel and in an open-field in southern Indiana this spring. Regardless of cultivars, we consistently noticed better fruit quality (higher sugar content, softer, and much cleaner) for strawberries grown inside of the high tunnel than grown in the open-field (Figure 1). I do not think[Read More…]

Figure 4. Ladybeetle, Orius nymph, lacewing larva, syrphid fly larva, and nabid bug predators of aphids found in strawberry plot. Photos by John Obermeyer and Laura Ingwell.

Aphids have been a particularly challenging pest to get under control in our high tunnel strawberries this year. They quickly colonized the strawberries we had growing all winter and took off as the weather warmed (Figure 1). In my first attempt to knock them back I introduced 2,000 lacewing larvae (22-Apr), too little too late. I decided to take the ‘opportunity’ at hand to evaluate four OMRI approved insecticide options. Applications began when populations were much higher than what growers should tolerate, so I would anticipate you would see even better results if you intervene at the first signs of infestation. Table 1 shows the products, active ingredient (A.I.), application rate and dates of applications. The change in aphid populations over the course of this trial are shown in Figure 2. In entomological tradition, I surveyed the aphid population prior to treatment (1-May) to get a baseline. As you can[Read More…]

This article discusses the abiotic factors that may cause deformed strawberry fruit. unevenly developed strawberry fruit (Figure 1): Frost damage is probably the most common abiotic factor causing misshapen strawberry fruit. Temperatures lower than 30°F kill the pistil (female part) of strawberry flowers. Depending on the extent of the injury and the stage of fruit development. The entire pistillate portion of the flower may be killed, which will result in the loss of fruit; Or a few pistils may be killed, fruit expansion stops at where pistils were killed. The damaged fruit then develops unevenly, resulting in misshapen fruit. Lack of wind for pollination is less likely a problem for field strawberry production but can be a concern for high tunnel production. Because high tunnels are typically closed at the peak strawberry blooming stage in order to attract heat. Air movement is very limited inside of the high tunnel that results in poor[Read More…]

Aphids have been a particularly challenging pest to get under control this spring. They quickly colonized the strawberries we had growing all winter in our high tunnels, and took off as the weather sporadically warmed up (Figure 1). In my first attempt to knock them back I introduced 2,000 lacewing larvae (22-Apr), too little too late. Four days after release I did not recover a single one. They were either hiding or did not survive. However, last week I found very large larvae (Figure 2), just one or two here and there. In the meantime, I decided to try out a few of the OMRI approved options. I will admit that at the time of the first application, the populations were high, and it explicitly states on the label for some of these products (BotaniGard® and Grandevo®), to begin applications at the onset of pest detection. That was not the[Read More…]

Figure 1:

Botrytis gray mold can cause disease on many different host plants, enabling the fungus to easily survive and disperse between crops. Host crops include flowers such as geraniums, vegetables such as green beans and fruit such as strawberries. The disease is favored by relatively cool temperatures and high humidity. We recently observed botrytis gray mold on tomatoes grown in a greenhouse and strawberry grown on a plasticulture system in the open field. Tomato: Gray mold of tomato is one of the more common diseases of greenhouse-produced tomatoes. Although it is often a minor problem, if left unchecked, gray mold can cause yield loss. Gray mold, or as it is sometimes called, Botrytis gray mold, may cause a light gray or brown necrotic lesion on leaves (Figure 1). The lesions on leaves are sometimes wedge shaped on the margin of the leaf. Stem lesions are a similar color and may encircle[Read More…]

Figure 2. Covering a strawberry field with a row cover.

Strawberries growing in the matted-row system are in the blooming stage. Open flowers cannot tolerate temperatures lower than 30°F (Figure 1). Strawberry growers should be prepared for the coming low temperatures this week. Row covers (Figure 2) can be effective in protecting strawberry flowers. In our earlier trial, 1.5 oz/sq row covers provided 4-6 degrees protection and successfully protected strawberry blooms in the earlier frost happened in middle April (the recorded lowest temperature was 24.5°F at Southwest Purdue Agricultural Center). Lighter row covers (0.05-1.0 oz/sq) provided fewer degrees of protection and double layers can be more effective. When using row covers for frost protection, be sure to have good soil moisture, sometimes running water through the drip line may add heat in the system. Apply row covers in the early afternoon to attract more heat before temperature drops. Although row covers can be effective in protecting strawberry blossom from frost[Read More…]

At Southwest Purdue Agriculture Center in Vincennes, IN. We are conducting trials to evaluate annual plasticulture strawberry production systems. Here are the updates of strawberries from different production systems. In a high tunnel, harvest of fall-planted strawberries started in early April. Cultivars Sensation, Radiance, Ruby June were early cultivars; followed by Beauty, Fronteras. So far, Radiance led the yield. Chandler, San Andreas, Camarosa, Liz and Camino Real were relatively later cultivars. In the open field, most cultivars of fall-planted strawberries were in full bloom. As mentioned in the article Strawberry Cold Protection Made a Difference, they are susceptible to frost damage. Cold protection is critical for them at this stage. Row cover was successfully used to protect the flowers from frost damage last week. Day-neutral strawberry cultivars planted on March 9, 2020 established well. Plants were slightly larger under low tunnels. Frost happened last week killed most of the initiated[Read More…]

Figure 2: Heavy aphid infestation of the buds of strawberries in a high tunnel.

This winter-spring has been my first excursion into growing strawberries in a high tunnel. It didn’t take much for our own Wenjing Guan to convince me to plant some; who doesn’t love to eat fresh strawberries? We planted them back in October and I just peeked at them every couple of weeks throughout the winter, looking for hungry herbivores wanting to share the impending treats. There were spider mites at first (Figure 1) and we made a few releases of the predatory mites Phytoseiulus persimilis and sachets containing Amblyseius (Neoseiulus) Californians. Figure 1. Two-spotted spider mites on strawberry leaves (above) and under a microscope camera (below). This spring, when the weather started warming up and the extra cover was lifted inside the tunnels we found less mites, almost none at all at this point, but an explosion of aphids (Figure 2) and an increasing presence of whiteflies (Figure 3). The[Read More…]

Figure 2. Cold damage on 'Popcorn' stage strawberry flowers.

Spring weather is unpredictable. One of the major risks associated with strawberry production is cold damage in the spring. Open strawberry flowers can not tolerate temperatures lower than 30°F, popcorn stage flowers and tight buds may tolerant temperatures low to 26 and 22°F, respectively. If strawberries are in the early blooming stage, the damage might be delayed harvest. However, if strawberries are in full blooming stage, low temperatures may cause dramatic yield loss. This is because inflorescences are initiated at day length <14h (June-bearing cultivars). If all the flowers were killed by low temperatures before setting fruit, there would be no more flowers for the year. In this article, we update the cold damage that happened last week on plasticulture strawberries in Vincennes, IN. Figure 1 is the recorded temperatures (°F) at the height of strawberry canopies from 2:00 pm Apr. 13— 1:00 pm Apr. 18. Temperatures dropped below 30°F[Read More…]

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