Ridge Gourd - Yellowing of young fruit set

Question: Ridge Gourd - Yellowing of young fruit set

responder: Christine H. Replied March 19, 2023, 5:44 PM EDT
response: Hello, My answer is going to be very general since there is information that would be helpful in diagnosing the problem.  First, were these ridge gourds planted outside or in a pot inside the home? Planting in a pot inside the home is acceptable as long as all the requirements are met.   Second, when were these ridge gourds planted? They can be planted any time of year as long as weather conditions are correct. Ridge gourds thrive in a hot climate. The ideal temperature is between 25-35 degrees C or 77-95 degrees F. Third, what are/were the soil conditions? Ridge gourds can be grown in a wide variety of soils, but they do best in sandy loam soil with excellent drainage and frequent watering. The application of organic matter will greatly improve production. Planting them on a trellis is preferable to letting them trail on the ground, where insects and diseases can overtake them.   Fourth, how much sun are/were the ridge gourds getting? They require at least 6-8 hours of sunlight per day.   Provided the plant is otherwise healthy and vigorous, it could be that either the plant is too young (does not have enough foliage yet) or that pollination has failed. Gourds and squashes frequently provide their own male and female flowers on different parts of the plant, so insect activity is required to move the pollen from one to the other. The male flowers need to be producing active pollen, and the females need to be receptive; this can fail when the plant is too dry, or the weather is too hot or too cold or rainy, or simply because the insect population is not dense enough to visit all the flowers. You may have to do hand pollination to get the plants to produce fruit.   It is also possible that the plants may have a calcium deficiency. (again, without more information, I can only speak in general terms). If this is the case, then the URL below can give you some hints on how to get the calcium into the plant. In most cases, if the soil is too sandy, the water cannot carry the calcium to the plant. If the soil is left too dry, that can also cause a problem with calcium uptake. Heavier soils and irrigated soils can easily bring calcium to the plant.   https://plantix.net/en/library/plant-diseases/700003/calcium-deficiency  The second URL has some general information about ridge gourd farming. https://www.agrifarming.in/ridge-gourd-farming-informationIf you can take pictures of the entire plant, including the undersides of leaves to see if there are insects present and then write back with some of the questions that were asked, a better diagnosis of your ridge gourd problem will be possible. You can reply to this email to continue the conversation.  I apologize for not being more specific, but the information provided did not allow for a more specific answer. I hope this was somewhat helpful.

responder: The Question Asker Replied March 20, 2023, 7:14 AM EDT
response: Hi Christine Appritiate your quick response.Photos are shared along with information.Ridge Gourd is F1 Hybrid.Planted Outside Current temp - Min 21°C Max 31° CWeather is clear , Sunny Humidity - 30-35%Planted on - 3 Rd Feb 2023Plant age - 45 daysSun light -  7 Am to evening 6.30 pmPrevious Crop - TomatoThere was water stress for initial 20 days. Proper fertigation was not given . Also there was weather change last week cloudy for 4 days, temp was dropped till 18°C . But now weather is normal as mentioned above.Started providing Calcium - calcium nitrate through drip and Spray .On Mon, 20 Mar, 2023, 3:14 am Ask Extension, <<personal data hidden>> wrote:

responder: Darin C.  Replied April 01, 2023, 2:54 PM EDT
response: Hi.  Thanks for sending more information and high quality photos. The good news is that I don’t see any obvious signs of insect problems or diseases, both of which can affect curcubits such as your ridge gourd. There is some minor leaf miner activity, but that shouldn’t be enough to produce the problems with fruit that you note. Here is a nice fact sheet from the U. of Kentucky that list the many types of insects and diseases that can cause problems here in the US. I assume that some/all of those can also cause problems in India, but I’m not certain about that. Overall, your plants look healthy, and your planting design looks good, so I also doubt that you are looking at a nutrient issue (at least not right now). That fact sheet says that gourds do not do well when temps fall below 60° F (about 15° C); since you have been above that, I don’t think that is the problem, either. However, maybe the weather change you describe affected pollination, which I suspect is your problem. This short description of poor pollination in curcubits from Texas A&M shows that fruits shrivel up when they don’t have sufficient pollination, and that is similar to the initial photo you sent as well as some of the ones you sent more recently. The fact sheet from the U. of Kentucky notes that each fruit must be visited 8-10 times for pollination within 24 hours (since that is how long the flowers are open). Any flower/fruit that doesn’t get that won’t develop. I wish I had a definitive answer, but I think that is the most likely option for what you are seeing.