No Mangos :(

[bangkokeddy]

My mangos produce a lot of flowers, but hardly any of them produce fruit, there is also a lot of black mould on the leaves. I have tried spraying, but perhaps I am using the wrong stuff at the wrong time, or just not being thorough enough. When (or what) should I spray and with what frequency? Which insecticide / fungicide is best? I do have a lot of weaver ants. I am quite fond of them but perhaps they have something to do with this. In addition, I'd like to set up an irrigation system - how much water, at what times and how often?

I've checked the web, can't qiute find anything suitable to answer my query.

Many

Thanks

[ozzydom]

My mangos produce a lot of flowers, but hardly any of them produce fruit, there is also a lot of black mould on the leaves. I have tried spraying, but perhaps I am using the wrong stuff at the wrong time, or just not being thorough enough. When (or what) should I spray and with what frequency? Which insecticide / fungicide is best? I do have a lot of weaver ants. I am quite fond of them but perhaps they have something to do with this. In addition, I'd like to set up an irrigation system - how much water, at what times and how often?

I've checked the web, can't qiute find anything suitable to answer my query.

Many

Thanks

Sounds like Sooty mould Eddy, white oil is the cure,it should be available from a farm supply shop in your area.

I have the same problem with fruit set on our mangos, I think the problem is shortage of bees to pollinate the flowers, am trying to locate a bee keeper in our area (North Issan ) with intention of buying a hive for the farm.

With most fruit trees ,a drip system is preferable, using two drippers per tree at opposite sides and laid at the drip line ,which is the outer edge of the trees foliage.

How much water depends on the soil type you have ,but generally less is better than more as it encourages root growth. Roots dont feed well in waterlogged conditions.

[bangkokeddy]

Sounds like Sooty mould Eddy, white oil is the cure,it should be available from a farm supply shop in your area.

I have the same problem with fruit set on our mangos, I think the problem is shortage of bees to pollinate the flowers, am trying to locate a bee keeper in our area (North Issan ) with intention of buying a hive for the farm.

With most fruit trees ,a drip system is preferable, using two drippers per tree at opposite sides and laid at the drip line ,which is the outer edge of the trees foliage.

How much water depends on the soil type you have ,but generally less is better than more as it encourages root growth. Roots dont feed well in waterlogged conditions.

Very helpful reply, thank you. I'll try the oil as you suggested. I can't say I've seen many bees around, the hive is a good idea. I tbought I saw a Humming Bird today, so perhaps that's just as good! I guess once the once I have the drip system the mangos will be larger, they are a bit on the small side this year as the soil is very dry. The soil is sandy around here (Rayong). Looking forward to a better crop next year. Thanks for your help.

Regards,

Eddy

[JungleBiker]

Hi Eddy,

Ozzydom has got half the story... The real problem is mango hoppers. They damage the flowers/buds hence no fruit. They also secrete (or is it excrete?) honeydew and that is what the sooty mold grows on. The sooty mold does not feed on the mango tree but it can block sunlight and thereby reduce photosynthesis.

To control the hoppers, normally two sprays of insecticide will do the trick but timing is crucial. You can spray Sevin (carbaryl), 60 grams per 20 liters of water. Spray once before flowering when flower buds start to emerge and then a second time after the tiny fruits have set. Don't spray during the main flowering period and do spray early in the day to avoid killing pollinators.

Regarding bees, http://www.hort.purdue.edu/newcrop/morton/mango_ars.html says: "Mango flowers are visited by fruit bats, flies, wasps, wild bees, butterflies, moths, beetles, ants and various bugs seeking the nectar and some transfer the pollen but a certain amount of self-pollination also occurs. Honeybees do not especially favor mango flowers and it has been found that effective pollination by honeybees would require 3 to 6 colonies per acre (6-12 per ha)."

Chownah might like to suggest some non-chemical methods, such as neem oil or neem extracts. Pruning is also advised to better aerate the canopy and make it less hospitable for pests like hoppers. Pruning is best done after harvesting the fruit.

With regards to irrigation, it is important not to irrigate after the end of the wet season until after flowering has started. Mangoes need a dry spell in order to flower, so if you watered all year round you would not get much flowering.

With sandy soil the water from drippers will tend to go straight down and not spread laterally so you might be better off with mini-sprinklers to wet a larger volume of soil/roots.

Best regards,

JB.

[ozzydom]

Interesting post JB , mango cultivation seems to be a touchy business , I have thirty odd trees of eight varieties scattered about ,I have never sprayed for hoppers but will give it a try.

Ag Dept of WA recommends pyrethium based sprays.

A lady I knew in Chiang Mai used to get great fruit set,which she attributed to fine spray watering while trees were flowering which is sort of born out by a local grower here who says for good fruit set you need a period of showers while flowers are out, he says these are the years of good crops when this occurs.

Maybe rain upsets the mango hoppers activities to an extent.

The problem with quoting website references is that you can always find another with a different point of view. Studies in Indonesia say honey bees are very important to good crops whereas in South Africa they say that honey bees have negligable impact on pollination.

Studies of honey bees in Australia showed honey bees as carrying up to 22,000 pollen cells after visiting mango inflourescences whereas wild bees carried less than 400 .

I suppose that with most conflicting studies ,the truth is somewhere down the middle.

We had a flowering at Xmas from which we got zilch fruit set , I changed over to hand watering foliage after I removed the dead flower bracts then we had another flowering and am going to have to prop limbs because of the heavy fruit set.

Mine is not to reason why etc.

cheers

ozzy

[Lickey]

Mrs and me where on farm last week, she said look, mango flower come early, its going to rain soon!!I said, Pan, no chance, this is january!! as i am writing this, its raining like crazy,,,,,, anoying thing is, the farm sprinklers are on a night time setting and working now, its near 2 ks to farm to turn off electric for pumps, Ah well, live and listen i suppose, but does early flowering mean more mangoes? cheers, Lickey,,

[mangofarmer]

Thanks All, very interesting postings! I have the same problem reported by bangkokeddy, many flowers small number of mangos. I have two mango fields 1) green mangos, flat area, small planting distance, many ants/termites 2) yellow mangos, sloop area, larger planting distance, no ants.

We have very little number of green mangos, reasonable amount of yellow mangoes. I also assumed it is shortage of pollinating insects as suggested by ozzydom, for the green mangoes (lot of ants/termites). I am not sure, it is only a theory.

Could ants reduce the number of pollinating insects leading to fewer mangos? Any observations, data on this?

Thanks, Dieter