Questions from the Master Gardeners’ Office

Question: Hello, I need help!!!!  My tomatoes have been attacked by the Colorado potato larvae, I have used 7 dust twice, and they keep coming back, I am afraid to use it any more… this AM, I was out picking them off the vines….any suggestions? I live in northeast Durham county.

Answer: Here is a great handout on managing the Colorado Potato Beetle and Larvae .  BT is effective on the small immature larvae and it can be soaked into the soil to reduce future generations.  However, if the larvae is close to maturity it is less effective.  Sevin is effective and o.k. to use on this insect, but to avoid complications with resistance I recommend rotating the pesticide you use.

Question: What is wrong with my plants several are exhibiting leaf curl?  Not just my tomatoes.  This is happening on my fruit trees and grape vines.  I have been spraying fungicides and insecticides I don’t know what is wrong.


Answer: The reaction you see is a classic symptom of 2-4D sprayed on tomatoes.  What more than likely has happened is there was residue in the spray tank from the time a broadleaf herbicide like 2-4D was last applied.  When the fungicides and insecticides were applied, the 2-4D residue was also applied to the plants.  It is very important to triple rinse and drip dry a spray tank after an application of a pesticide – applying the leftover rinse (residue) in the manner it was intended.  An easier solution to help prevent this from happening again is to have at least 2 spray containers and label them – one with (herbicides) one with (fungicides/insecticides).  Regardless – always be mindful that leftover residue in the tank will be applied to plants in the next application and can have negative consequences.

Question: What is this plant?  The birds love it.


Answer: Serviceberry – Amelanchier arborea .  The Durham County Extension Master Gardener Demonstration Garden has one and the berries are eatable for human consumption and they taste good.  Similar to a blueberry.

Question: What is this weed and how do I get rid of it?


Answer: This is a parasitic weed known as dodder.  It has no chlorophyll and is difficult to control.  In ornamental beds once established it must be hand weeded out as most of the post emergent pesticides will also kill the plant that it covers.  There are some pre-emergent pesticides available that will prevent it from establishing provided it is put out early before germination.  Sanitation and removal is important.

Thanks to Michelle Wallace, Consumer Horticulture Agent, for sharing these questions and answers.