March/April 2023 - 14

PEST MANAGEMENT
Thought to originate in the
Southeastern U.S., Gill's mealybug
so far has not been reported in
Arizona or New Mexico. Since the
females do not fly, and California
harvesting equipment is not
typically transported to those
states, hopefully the mealybugs
will not hitch a ride to the pistachio
orchards there.
(Senstar, IRAC 24 & 7C), sulfoxaflor (Sequoia, IRAC 4C),
flupyradifurone (Sivanto, IRAC 4D) and phosmet (Imidan,
IRAC 1B).
Pistachios, however, have since been removed from the
sulfoxaflor label due to higher-than-expected residues.
Further two-spray trials showed that Movento in May
plus Assail or Sequoia in July both worked well. In addition,
afidopyropen (Sefina, IRAC 9) did well at double the
prescribed rate, so the manufacturer is investigating getting
the double rate approved for pistachios.
To prevent insect resistance, Haviland recommends
rotating the insecticide from year to year, even if only one
spray is used. For two sprays per year, the two should never
be the same insecticide.
Postharvest treatment is not recommended for two
reasons. First, it may kill beneficial predators at the time
they are most active; second, spraying is not worth the
cost because more than 99% of the nymphs die in the
winter anyway.
Second generation of Gill's mealybug, in late July.
Challenges with resistance
Treatment for Gill's mealybug has become more
complicated in the past few years. Numerous observations
indicate that insecticides are not working as effectively as
when they were first registered in the mid-2000s. When
first launched, one application of any of these products
was adequate for season-long control. Now, in some cases,
a follow-up spray in late July is needed to kill the second
generation of crawlers.
The population skyrockets in early August if not treated,
so the timing of that July spray is crucial.
" Once the nymphs are numerous and coated in wax,
around Aug. 1, further spraying is useless, " Haviland said.
To ensure the spray is timely, the grower should monitor
frequently for crawlers in late July and purchase product
ahead of time.
Biological options
Biological options are available for organic growers.
Azadirachtin (Aza-Direct, a neem derivative) and
Gill's mealybug female adults and crawlers in a
" cotton candy " nest in May.
14 MARCH/APRIL 2023

March/April 2023

Table of Contents for the Digital Edition of March/April 2023

March/April 2023 - 1
March/April 2023 - 2
March/April 2023 - 3
March/April 2023 - 4
March/April 2023 - 5
March/April 2023 - 6
March/April 2023 - 7
March/April 2023 - 8
March/April 2023 - 9
March/April 2023 - 10
March/April 2023 - 11
March/April 2023 - 12
March/April 2023 - 13
March/April 2023 - 14
March/April 2023 - 15
March/April 2023 - 16
March/April 2023 - 17
March/April 2023 - 18
March/April 2023 - 19
March/April 2023 - 20
March/April 2023 - 21
March/April 2023 - 22
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March/April 2023 - 24
March/April 2023 - 25
March/April 2023 - 26
March/April 2023 - 27
March/April 2023 - 28
https://www.nxtbook.com/greatamericanmediaservices/NNG/march-april-2024
https://www.nxtbook.com/greatamericanmediaservices/NNG/january-february-2024
https://www.nxtbook.com/greatamericanmediaservices/NNG/november-december-2023
https://www.nxtbook.com/greatamericanmediaservices/NNG/september-october-2023
https://www.nxtbook.com/greatamericanmediaservices/NNG/july-august-2023
https://www.nxtbook.com/greatamericanmediaservices/NNG/may-june-2023
https://www.nxtbook.com/greatamericanmediaservices/NNG/march-april-2023
https://www.nxtbook.com/greatamericanmediaservices/NNG/january-february-2023
https://www.nxtbook.com/greatamericanmediaservices/NNG/november-december-2022
https://www.nxtbook.com/greatamericanmediaservices/NNG/september-october-2022
https://www.nxtbook.com/greatamericanmediaservices/NNG/july-august-2022
https://www.nxtbook.com/greatamericanmediaservices/NNG/may-june-2022
https://www.nxtbook.com/greatamericanmediaservices/NNG/march-april-2022
https://www.nxtbook.com/greatamericanmediaservices/NNG/january-february-2022
https://www.nxtbook.com/greatamericanmediaservices/NNG/winter-2022
https://www.nxtbook.com/greatamericanmediaservices/NNG/fall-2021
https://www.nxtbook.com/greatamericanmediaservices/NNG/summer-2021
https://www.nxtbook.com/greatamericanmediaservices/NNG/winter-2021
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