Bagrada bug adults generally begin to appear on direct seeded fields and transplants
in early September. In fact, trials conducted on untreated broccoli plots at YAC
have shown that mid-September has historically been the time that bagrada begin
to show up in large numbers; peak abundance of bagrada bug has occurred from late
September to early October (see graphs below). However, there has been a trend of
lower bagrada bug abundance since 2012, and last fall was the lightest we’ve recorded
bagrada populations since we started tracking them in 2010.
So far this season, we’ve yet to see a bagarada here at YAC, but reports of bagrada
in commercial cole crops are beginning to trickle in from PCAs, albeit very few.
Similarly reports out of Imperial Valley and Coachella suggest that populations
are light there as well. So, what should a PCA expect for this season? Can’t say
for sure, but don’t be complacent just because you’re not finding a lot of bagrada
adults on your first few fields. It would be wise to assume they will eventually
show up in some intensity in some of your acreage, and you should prepare for them
accordingly. Here are a few management tips to consider. (1) We’ve learned through
research that when monitoring for bagrada bugs at stand establishment PCAs should
focus on fresh feeding signs on new plant tissue, and adults later in the day when
they are most active. (2) Research in the field has also indicated that direct-seeded
and transplanted crops are susceptible to bagrada bug infestations during stand
establishment and up to the 6-leaf stage. Furthermore, it doesn’t take a large number
of bagrada adults to cause significant stand losses or crop injury. In untreated
plots, we have consistently observed significant damage (15-20% blind plants) to
direct seeded plants during the first 7 days after emergence (cotyledon to 1-leaf
Stage) with only finding an average of 1 bagrada adult / 6 row. (3) Thus, we recommend
that if you readily find 5% or more of plants with feeding signs during stand establishment,
control should be initiated immediately. This can include chemigation or aerial
applications with pyrethroids. Contact insecticides such as pyrethroids, Lannate,
and Lorsban should be used once stands are lined out and pipe is pulled. After stands
are established and plant size increases up to the 2 leaf stage, or on tagged transplants,
consider alternating to dinotefuron (Venom/Scorpion) for protecting plants from
bagrada feeding. This neonicotinoid will also provide knockdown of adult whiteflies
and nymphs. (4) Also, growers who planted with Nipsit (clothianidin), should begin
to closely monitor for fresh feeding damage around 14 days after emergence. More
information on bagrada bug management on fall cole crops can be found in:
Bagrada Bug Management Tips for the Low Desert.
Name the insect pest that caused the damage
to this cantaloupe leaf. - Looper Damage
Remember, When in Doubt . . . . . “SCOUT”
Click picture to listen to John’s update
|
