Xtremehorticulture

Xtremehorticulture of the Desert

Remove Bottom Leaves in Cabbage to Reduce Pest Problems

Leave a Comment / aphids, broccoli, cabbage loopers how to control insects, cole crops, whiteflies /

Q. What can I use for bugs on my cabbage now? A. The usual bugs on cabbage are aphids, whiteflies or cabbage looper. First off, remove the bottom leaves on the plants near the ground. They are nearly in full shade and no longer contribute much to the plant. Cabbage leaves too close to the ground and cannot be sprayed on the underside. Most bugs will collect on the undersides of the leaves. Once the lower leaves are removed it is easier to spray the bottom of the leaves, pointing the nozzle upwards. These leaves are close to the ground, the underside is a great place for bugs to hide from predators and impossible to spray. In older plants they are tough so you will need to cut them off. These insects also like to gather between leaves at the base. This is where you find cabbage looper eggs deposited. This is the white butterfly that likes to hang around cabbage and cabbage related vegetables, lay eggs that hatch into green worms that chew holes in the leaves. A sure sign of insect problems are holes in the leaves. The plants should be sprayed at the first sign. Cabbage butterfly lays its eggs deep inside the crevices of the leaves. This area needs Bt or Spinosad sprays or dust. You should have on hand at three to five of these organic sprays; insecticidal soap, Neem oil, Bt, pyrethrin and Spinosad and a good pump sprayer. Soap sprays will be used most often; twice a week. The others are applied less often, usually as needed. Spray on top of the leaves as well as the undersides where most insects will hide and feed. Bt sprays like Dipel or Thuricide are used against pests whose adult forms are moths such as the cabbage looper. This spray or dust is applied between the leaves and left undisturbed for a few days so it can work. Some insecticides say Bt right on the label while others may say Dipel, Thuricide or worm or caterpillar killer. Whiteflies are controlled with insecticidal soap, pyrethrum or Spinosad sprayed alternately, a few days apart. Sprays need to be directed at the pests so it must be applied to tops and bottoms of leaves. A popular brand of insecticidal soap After harvest you will still have bugs in the cabbage and other leafy greens. A rinse in a clean sink with water containing 1 tablespoon of household bleach per gallon will kill any bugs remaining. Rinse all vegetables with clean water before preparing them.

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Whiteflies Destroyed Vegetable Crops

4 Comments / damage to vegetable crops, whiteflies /

Q. I am new to gardening in the desert and am surprised at my success thus far!  That is, until the whiteflies came. It is August and they are on EVERYTHING!!  I started with insecticidal soap on the undersides of the leaves and I see dead flies there. I am getting ready to plant all new Vegetable crops for fall but need to get a handle on these flies before subjecting new plants to these insatiable pests. A. Whiteflies are a very tough insect to control once they get established in the numbers you are talking about. Females lay a couple hundred eggs at a time and these hatch and develop into sexually mature adults in about six weeks. Whiteflies on pomegranateNoticed they are on the bottom sides of the leaves. Conventional pesticides have not been very effective on whiteflies due to the development of resistance to applied pesticides. Now we rely on a more integrative approach to try to get a handle on controlling them. This includes the use of oils and soaps when temperatures permit, yellow sticky boards that are renewed on a regular basis, reflective mulches such as aluminum foil, planting trap crops such as squash, hand picking heavily infected leaves early in the season, hand vacuuming, and others. Yellow sticky trap in greenhouse. You need to stay on top of this pest early in the season if you expect some control. Their numbers explode when it gets hot. When plants are still small, remove the bottom leaves close to the ground. These usually get infested first and they are impossible to spray on both top and bottom sides of the leaves which you must do. Get on a regular spray program at their first sign, alternating with soaps and oils. Spray at least weekly both the underside and tops of the leaves. You will need a backpack sprayer if you have lots of plants or you might consider purchasing a fogger to apply pesticides. Solo backpack sprayer Foggers are quite effective but must be used when there is no wind. Use yellow sticky cards supported over the crop and replace it weekly. These can be used to help predict when to spray. Trap crops that attract whiteflies, like squash, may also help. Squash plants strongly attract whiteflies and help to deter them from infesting other crops in the garden. Sometimes it may be easier to remove severely infested plants and replant.

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Black Spots on Watermelon Leaves Could Be Several Different Insects

Leave a Comment / aphids, black specks, disease, insect, melons, squash bug, whiteflies, whitefly, Yellow sticky traps /

Q. I have attempted to grow watermelons for the first time last summer and everything was looking good until it got hot. These tiny black specks appeared on the back of some of the leaves.  I was told it was aphids but they weren’t sure.  I hope you can see them clearly from the picture I’ve attached. Should I use insecticidal soap as recommended or something else?  A. I tried to magnify the picture so I could see the black spots better. I was curious if these were in fact from insects or not. I could not see it clearly but whatever it was, it appeared that it was no longer a problem and the leaves seemed nice and healthy.             Aphids are cool weather insects and so when the heat hit they should have disappeared. The big insect problems for you on watermelon would be aphids earlier in the season during cool weather, squash bugs shortly after planting and whiteflies (during the heat).             Yellow sticky traps can provide a method to determine if whiteflies are a problem or not. I will post a short video on my blog on how to make these rather than buy them. They are handy to place in the garden for insect monitoring.             Soap and water sprays are good but must be done about every three or four days and the underside of the leaves must be sprayed as well. Squash bugs are nasty and can be vacuumed or hand-picked or delay planting by seed until after June 1. If you are hand picking or vacuuming squash bugs then be diligent for about three or four weeks and keeping the plants cleaned off every couple of days by hand until mid-June to avoid most of the problems with this insect.       Thanks to Garry Pearson, Lead Greenhouse Managerat UC Davis CAES,                 Department of Vegetable Crops, during his presentations on greenhouses in Afghanistan.

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Leaf Munching on Grapes, Whiteflies, Leafhoppers

4 Comments / grape insecticides, hornworms, leaves disappearing, whiteflies /

Q. My grapes leafs are gigantic this year after the big pruning; but something is taking big munching bites out of the leaves – I don’t see any thorn worms?  Any ideas? -Jeri One of the hornworms as larva or caterpillar A. It is probably hornworms this time of year. Put on a spray of Bt now or spinosad. Repeat it in about two weeks. Use spinosad if you had leafhoppers last year. They are tiny and they jump. That should keep them pretty clean. Q. I enjoy your articles in the newspaper. Thank you for your insights into my garden. I have a five year old grapevine.  Each year I have an infestation of tiny white flying insects.  I have tried traditional sprays with no success. What are they, and how do I get rid of them?  BTW – The hummingbirds love them.  The birds will cause the insects to become airborne, then pluck them off in mid-air. -Fred Leafhopper damage to grape leaf A. It is possible that they are either leafhoppers or whiteflies. I have seen leafhoppers more often than whiteflies on grapes. However your description fits whiteflies better than leafhoppers since you said they fly and are white.             Leafhoppers are usually darker in color, green or brown or a combination of both but jump into the air rather than fly. Both are hard to control but soap and water sprays are good when they are very young.             It is getting late now as this should have been applied in late April or early May if using soapy water. You can also use insecticidal soap. It is in the right concentration and does not have potential problems as you might have with soaps or detergents that have skin conditioners or scents added. Leafhopper damage cropped and enlarged upper surface             Be sure to spray the undersides of the leaves which is where they are most likely found but go out and find where they are and direct the spray on the insects, not just on the plants. The insecticidal soaps have no residual so if they land back on the soapy surface of the leaf it will not harm them.             The soapy water MUST come in contact with the insect or it will not work. If these are truly whiteflies then use a fruit spray that contains the words pyrethrums, permethrin, cypermethrin, pyrethroids, etc. you get the idea. It should have “ethr…” in words in the ingredients. There are lots of different kinds.             If this is leafhoppers you can try applying spinosad this time of year but it is starting to get late for this application. It should have been done in May but try it.

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Borers in Fruit Trees and Buggy Grapevines

1 Comment / flying insects, grape pests, jumping insects, leafhoppers, whiteflies /

Q. Through the years I have planted many fruit trees and lost many to borers especially stone fruit trees. My grape vines have been devastated by whiteflies to the point where I could not harvest one healthy grape leaf last season. I have tried soap water but to no avail. Also, I have tried Lindane against borers but their work keeps appearing on my plum trees. A. Whiteflies can be a difficult problem. We have not experienced whiteflies on grapes. The closest insect which might be confused with whiteflies, and is a common problem on grapes, are leaf hoppers. Please make sure you are not confusing whiteflies with leaf hoppers because the treatment is very, very different. Whiteflies are like dandruff and usually fly in a cloud of small white insects when the leaves are disturbed. They usually leave a sticky substance on the leaf surface from feeding. Click here to see some Whitefly pictures Leafhoppers on their backs, maybe 1/8 inch long Leaf hoppers on the other hand jump and are brown in color but they can accumulate in thousands on grapes and jump in your face, your nostrils and eyes as you pass the grapes and disturb the foliage. Both are nearly the same size but whiteflies are white and fly more delicately while leaf hoppers jump and are brown. If soap and water sprays are used religiously on the grapes when these insects are small it should give fairly good control. If soap and water is delayed until they are mature adults, then control is probably iffy at best. Whiteflies are listed on the University of California and pests lists for grapes but not a common pest. Leafhopper feeding damage on grapes Click here to learn the Common Pests of Grapes If they are whiteflies then sprays such as pyrethrins might be a good choice but the label must include grapes if you are to use it within the law. If these are leaf hoppers, then sprays applied in May such as spinosad might be useful when this insect is still juvenile. In both cases when these insects are adults they are much more difficult to control. Sap oozing from cut limb of plum Regarding the borers in your plum tree, Plum can be attacked by boring insects but it is not as common as some other fruit trees like peach, nectarine or even apple. Please check and make sure that this is in fact borers causing damage and not just sap oozing from a stressed out tree. When plum is stressed from water, intense sunlight or heat stress they will ooze sap. There is no insecticide you can use on fruit trees once they are attacked by boring insects and still safely eat the fruit in my opinion. Most insecticides recommended after fruit trees have been infested are usually systemic in nature. This means that the insecticide could also be in the fruit, not just on the surface.

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