Bacterial wilt is a serious pest of cucumbers and melons. This disease is caused by the bacterium, Erwinia tracheiphila. However, it is spread by the striped or spotted cucumber beetle. Most management schemes have concentrated on controlling the cucumber beetle in order to lessen the severity of bacterial wilt. Currently, management of bacterial wilt often takes the form of a soil applied systemic insecticide such as Admire Pro® at transplanting and follow up pyrethroid products applied foliarly about 3 weeks post transplanting. The pyrethroid applications are made when the 1 beetle per plant threshold is met. Every year, there is a melon variety trial at the Southwest Purdue Agriculture Center in Vincennes, IN. In 2018, the trial included several specialty melon varieties. We noticed more bacterial wilt than usual (Figure 1). Therefore, we decided to rate the varieties to see if there were any differences in susceptibility. Figure 2 shows[Read More…]
This disease was recently observed in a tomato greenhouse. This article will review tomato spotted wilt virus symptoms, biology and management. Tomato spotted wilt virus (TSWV) and the closely related Impatiens necrotic spot virus (INSV) are usually observed in greenhouse or high tunnel situations. Both TSWV and INSV affect many hosts, including vegetables and flowering ornamentals. Symptoms vary according to host, stage of plant affected and environmental conditions. Both diseases can cause stunting, yellowing, necrotic rings, leaf mottle and more. Figure 1 shows a tomato leaf with a necrotic mottle caused by TSWV. Figure 2 shows tomato plants stunted as a result of infection by TSWV. Additional symptoms may be viewed here . Since the symptoms of these two viruses vary, plants with suspicious symptoms should be submitted to the Purdue Plant and Pest Diagnostic Laboratory for confirmation of virus symptoms. TSWV and INSV cannot spread without thrips. Thrips are small[Read More…]
Two types of injury on young warm-season vegetable plants are caused by low temperatures: frost/freezing injury and chilling injury. Frost/freezing injury occurs when temperatures drop below 32°F. Ice formation in plant tissues cut cell membranes. When the tissue thaws, the damage results in fluids leaking from the cell, causing water soaked damage. Frost/freezing injury is detrimental to warm-season vegetables, such as melons, cucumbers, tomatoes, peppers, beans. To avoid damage, the best way is to plant warm-season vegetables later in the spring, after the last frost has passed. However, weather is difficult to predict, and there is a growing trend of planting early to achieve early harvests. For the early planted warm-season vegetables, here are a few suggestions that may protect plants from low temperature damages. Covering. The idea of covering the seedlings is to create a microclimate around plants. Because the heat accumulated in soil irradiate back at night, covering[Read More…]
Chilling injury occurs when temperatures are above 32°F and below 55°F. The plant tissue becomes weakened that leads to cellular dysfunction. The most noticeable visual symptom of chilling injury is leaf and hypocotyl wilt (Figure 1). This is caused by the rapid decline in the ability of roots to absorb and transport water. It also caused by the plant’s reduced ability to close stomata. If temperatures do not improve, plants may be killed. Low temperatures also have an effect on mineral nutrient uptake of the plants. Absorption of ions by roots is difficult, as well as their movement in the above-ground parts of the plants. As a result, chilling injured plants often show symptoms similar to nutritional deficiency. Although warm-season vegetables are all susceptible to frost/freezing damage, their susceptibility to chilling injury varies among plant species. Pepper plants seem to have greater difficulty recovering after chilling injury compared to tomato[Read More…]
Basic Aspects of High Tunnel Soil Fertility Management – (Petrus Langenhoven, plangenh@purdue.edu, 765-496-7955) – Spring has arrived! Every high tunnel grower is now thinking of planting summer vegetable crops in high tunnels or has already planted. Whichever scenario applies to you, I hope that you have submitted soil samples or are in the process of submitting samples to your closest laboratory. Have you analyzed your irrigation water? It will be a good idea to send a water sample along too. There is a lot of important information locked up in your water and soil test results. The results will help you to plan and manage your high tunnel fertility program. Remember, growing in a high tunnel is like growing crops in an irrigated desert. Natural rainfall is unavailable inside your high tunnel and therefore all your plants water needs are satisfied through an irrigation system. Fertilizer needs could be addressed[Read More…]
The rain seems to keep falling, barely providing time for things to dry out and start planting! The last few weeks has experienced up to 2” above normal precipitation – particularly for west-central and southern Indiana, which is near the 125th-125th percentile. Warm days seem to be relatively few and far between, causing a slow start to growing degree-day (GDD) accumulations. While it is still early in the season, Indiana has only accumulated about 30-60 GDD units, with the few amounts to the north. Hard freezes (<= 28°F are still in recent memory, with the most recent hard freeze occurring just last week (April 1-3). For April 8-16, precipitation forecasts are predicting 1.5”-2.5” of rain, with the higher amounts expected in the southern half of the state. There is still a 25-50% chance of a 32°F freeze occurring in southern counties and over a 90% chance of a freeze occurring[Read More…]
On April 1, 2019, Dr. Hazel Wetzstein, Head of the Department of Horticulture and Landscape Architecture, announced a change in leadership for the Indiana Horticulture Congress. “I am pleased to announce that Petrus Langenhoven and Kyle Daniel have agreed to serve as Co-Chairs for the Indiana Horticulture Congress, effective immediately. They bring a wealth of information and experience and I am looking forward to the leadership they will bring to IHC”. Peter Hirst, will be stepping down as chair. He is going to maintain a program in Pomology in the HLA Department and will assume an active international role as Assistant Director in International Programs in Agriculture (IPIA). “We all wish to thank Peter for his dedication and many years of service as IHC Chair. It is important to note that the past successes of Hort Congress would not have been possible without the dedicated efforts of Lori Jolly-Brown and[Read More…]
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