I live 10 blocks from the Pacific Ocean and I have a grapefruit tree that has lost many of its leaves and has lots of twiggy branches. I water it occasionally but we have had a very bad drought year here in Southern California so maybe I should water it more. It has oozing gum on its bark, which may be gummoris (a word I just learned from reading your very helpful website), but there might also be a nutrition problem. The leaves don't look too bad and the fruit this year was full. I pulled a lot of it off this week to lighten the tree's weight burden, hoping that this could help to revive it. I have had this house for 3 years and the tree was pretty healthy the first two years. I staked it with nutritional stakes at the tree's rain line the first summer I was here. Maybe I need to do that again. (My neighbor has the exact same tree and his is healthy and fine.) Would you glance at these photos and kindly send me any wisdom that you can? One is a close-up on the bark, another a view of the entire tree, and another from inside the canopy. I would really appreciate any help you can offer Jenny in Long Beach
It looks like your tree is suffering from a disease called Foot Rot. Foot rot, also called gummosis, is the most serious disease caused by Phytophthora spp. Infection occurs near the ground level, producing lesions. Usually, the cambium and inner bark are damaged, but the outer bark remains more or less firm with cracks through which abundant gum exudes. Lesions can spread around the circumference of the trunk, killing the cambium and slowly girding the tree. If this occurs, the tree dies. If the lesions cease to expand or the fungus dies, the affected area is surrounded by callus tissue and begins to heal. Lemons, limes, sweet oranges and grapefruit are all very susceptible. Symptoms of Foot Rots are: Necrotic lesion present in the trunk near the ground. Brown stain or gum and creases seen at bud union. Trees lose vigor and have thin canopy. Lesions can be present on trunk and major limbs. Scaling of outer bark, but bark alive. Bark is dead in areas around sites where gum exudes profusely from trunk. Bark dead near soil line; plaques of white fungal mycelium under the bark of large roots or trunk. Post plant chemical control may be warranted if cultural controls are inadequate. Fungicides Metalaxyl and fosetyl-Al. Usually applications of fosetyl-Al and metalaxyl are alternated to minimize the development of resistance to the fungicides. Improper irrigation is a major cause of this disease along with grafts that are to near the soil. You should contact your county agent for professional assistance with your tree. I offer you only general information, to your tree's probable problem, but cannot give you exact advice, because your tree is a fruit bearing mature with eatable fruit. In order to save your tree, if possible, you need to have it examined QUICKLY. Good luck, - Millet
I suggest you contact your local Los Angeles County Cooperative Extension office and see if you can have someone come out and take a look at your tree for a probable Phythopthora gummosis problem. If they will not come out ask them where you can get a hold of some Agricultural strength Ridomil to use as a topical systemic spray or Aliette to paint on the entire trunk from the lowest branch all the way to the ground. Then find some white latex paint to paint over the Aliette application or the Ridomil spray once it dries. UC IPM: UC Management Guidelines for Phytophthora Gummosis on Citrus Step one is dealing with the trunk and trying to give this tree more frequent deep waterings. The latter can be done with a hose but we do not have a lot of area to supersaturate at the present time. Your ground may not allow for deep watering and that can be an issue here. (I used to live in nearby San Pedro up on the hill heading into Palos Verdes estates. I know how quickly saturated some of the soils in the vicinity can get). I suggest you also ask your Cooperative Extension Farm Advisor or County Master Gardener who they recommend for an arborist to come in and clean out the dead and deadened wood in the top of the tree and do have them check for scale, perhaps Black scale by the looks of the damage I am seeing. Once the trunk is treated and the sap exudate (gummosis) has been slowed down and stopped and the tree topped, pruned to clean it up and shape the tree, then we go after the nutrient imbalance or soil related issues you have with this tree. Jim
