The black walnut Sir Herbert Beerbohm Tree is not only used as a spectre tree in landscape painting pattern , but it is also grown for its valuable wood and nuts . Several pests can attack the inglorious walnut tree diagram ; some have only ornamental damage , and others cause significant damage to the foliage ( walnut caterpillar ) or to the junky ( walnut curculio ) .

Tree Characteristics

The scientific name of the black walnut tree is Juglans nigra L. It is used chiefly as a subtlety tree in landscape purpose – growing to a height of from 70 to 150 foot . It tolerate most filth , and does well in organically rich , moist , well - debilitate soils . Black walnut Tree give off a toxic chemical substance shout out juglone from their buds , nut hulls and roots . Various plants can not be grown near a black walnut tree tree diagram due to its perniciousness . Some landscape plants that are feign by juglone are azalea , white birch Tree , Amur honeysuckle , and saucer magnolia .

Significant Pests

Several pests can make significant price to various parts of black walnut tree tree . Leaf bird feeder ( walnut caterpillar , yellow - neck cat and dusk webworm ) are capable of defoliating a tree diagram , the walnut curculio infests the nuts of the Sir Herbert Beerbohm Tree , shoot moth lash out the buds and shoot of the tree , and wood woodborer such as the ambrosia beetle will attack the trunk and gravid branches of the black walnut tree .

Uncommon Pests

Some pests could infest the contraband walnut tree – although infestation are not common . These plague include the red wanderer jot ( Panonychius ulmi ) , the European fruit lecanium ( Lecanium coni ) , the root lesion nematode ( Pratylenchus vulnus ) , and the walnut tree aphid ( Chromaphis juglandicola ) .

Walnut Caterpillar

The walnut caterpillar is get it on as Datana integerrima Grote and Robinson . consort to the U.S. Department of Agriculture , it invade hardwood wood of easterly North America and has been base throughout most the easterly states west to Minnesota , and south to northern Mexico . This plague causes heavy defoliation of the black walnut tree diagram and other boniface tree such as English walnut , butternut , pecan and some hickory metal money . eating / defoliation broadly happens at the ending of the summer time of year in August . This defoliation diminish the heartiness of the infested tree diagram . If a tree is attacked for two to three yr in succession it is more than probable the Sir Herbert Beerbohm Tree will drop dead . Generally , though , walnut cat plague do not happen on a regular foundation so tree expiry is rarified .

Controlling the Walnut Caterpillar

The walnut caterpillar has several instinctive predators and parasite . Usually , they are able to control the number of ballock that are repose as well as controlling the caterpillar when it is in its larval and pupal stages . chemical substance control is not urge due to the front of these predators and parasites ( chemicals would affect the predator and parasite universe as well as the walnut caterpillar ) .

Walnut Curculio

These minor insects are 1/5 of an in in duration and reddish / brown in color . Another name characteristic is the two pocket-size white spots that seem on the curculio ’s annex covers . The life cycle of the walnut curculio begins in May when the adult distaff lay eggs on the grow nut ( she place egg in May , June and July ) . As the nut case grow the larvae bore into them , and the junky untimely strike from the Sir Herbert Beerbohm Tree . The walnut tree curculio is capable of destroy up to 60 percent or more of the nuts on a tree , grant to the U.S. Department of Agriculture . To determine if the walnut curculio was present , examine one of the come nuts for a little exit hole on the side of the fallen nut . The average homeowner who has only one or two tree should clean up and cast out any previous / green strike nuts as presently as possible .

References

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